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Mark Calder
10-13-2011, 09:50 AM
Hello new board!! my name is mark Calder, I'm the designer of the old Wren ultralight, I have a new Ultralight named the Robin that I am getting ready to cover. I put this Blog together that goes back a few yers, it covers all of the design and build of the Robin.

Please take a look and give me some feedback if you will. Eventually i will be selling plans. My near term goal however is to have the robin to next years Lakeland Airshow

736http://robinultralight.blogspot.com/

rosiejerryrosie
10-13-2011, 10:15 AM
Mark, I've been following your blog for a year or so. Great work - great explanations of your progress - can't wait to see the Robin in the air. Keep up the good work!

Mark Calder
10-26-2011, 06:29 AM
I just completed a light weight fairing for the Vert Fin/Rudder. its a pretty interesting process if you have never worked with foam, glass and Gel coat. The final completed fairing weighs 3/4 of an ounce.

This is a foam technique I use to make compound contour parts. There are quite a few references to this in my blog and I think the average homebuilder will find this quite useful.
http://robinultralight.blogspot.com/2010/09/wing-tip-master-model-process.html

http://robinultralight.blogspot.com/2011/03/canopy-frame-and-yarmulke.html

http://robinultralight.blogspot.com/2011/04/engine-cowling.html


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Mark Calder
11-07-2011, 07:46 AM
I finished the fairings, the canopy, fairings, tip caps and instrument panel are all in for final paint. I installed and calibrated Jim Weibes Belite fuel gauge. I have one final job before I start to cover the Robin, I neeed to rearrange my shop so I can reattach the wings and rig the aileron cables. Thats the final job!!! I'm starting to see the light at the end of the tunnel.

Mark Calder
11-13-2011, 06:26 PM
this is about as light as you can get, Belite gauges are almost zero weight, Thank You Jim Weibe!!!


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There are more pictures of the progress on my Blog http://robinultralight.blogspot.com/

Mark Calder
11-16-2011, 09:49 PM
I just updated my blog http://robinultralight.blogspot.com/ with additional info on the instrument and canopy frame modification. i completed the tail fairing and am completing the final wiring. the next step ids to re rig the wings and then rig the aileron cables. Covering will follow shortly after.
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Mark Calder
11-29-2011, 08:48 PM
just posted an update. http://robinultralight.blogspot.com I am in the process of completing the canopy installation and instrument panel wiring. I Have tested all of Jim Weibe's Belite instruments and I an report they were flawless.

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Mark Calder
12-11-2011, 05:38 PM
I finally finished the canopy. I installed the Windshield, Latch, centering clips and engine primer. I updated all of this on my blog. http://robinultralight.blogspot.com/1233

rosiejerryrosie
12-12-2011, 08:33 AM
Mark, That's not an airplane, it's a work of art....

Mark Calder
12-19-2011, 08:17 PM
My baby just left the ground!! about 4 feet to be exact!! Ii built a stand to elevate the plane so I could install the aileron cables. The last time I had the wings on, the center controls were not complete and the aileron cable could not be routed. Here are some good views. I should be ready to cover the Robin starting Saturday. It wont take but a few days to finish that job and then its on to final finish. I do believe I will be ready for taxi testing by the middle of January. man this has sure been a long haul!!! One of the pictures shows the Friese Type aileron pretty well http://robinultralight.blogspot.com/ (http://robinultralight.blogspot.com/)

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Mark Calder
12-24-2011, 07:10 PM
I am finishing up the final few jobs before I start to cover her. I anticipate, I will be covering by Tuesday of next week. I updated my blog with more pictures. http://robinultralight.blogspot.com/



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Mark Calder
12-29-2011, 09:05 PM
I started covering the tail Feathers, There was a bit of a learning curve, but by the time I started the second surface, everything went smoothly. I posted more pictures and an update on my blog. http://robinultralight.blogspot.com/


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TomHenry3
12-31-2011, 10:08 PM
Your Robin ultralight airplane is a very attractive aircraft, ultralight or not !
Thank you for sharing your build.
How tall of a pilot is it designed for? (I'm 6' 6" tall)
Do you sell plans for your shop from Holland, MI.
It is right along the lines I have been thinking but didn't know the footings could be in top of insulation.
I thought that might lead to settling of the foundation.

Mark Calder
01-02-2012, 02:05 PM
Hey Tom. There are Styrofoam concrete forms that are used for the footings, that's what I used. I used 2" thick Styrofoam sheeting for the floor. The process starts with a level grade of sand, the grade is set 2 inches deeper than usual. Rebar standoffs are driven through the foam and square mesh is set on top of the foam (spaced off with small stand offs). This insulates the pad. Concrete is poured normally on top of the foam. If the sand base is level, workman can walk on it without breaking it. The rest of the shop is a straightforward 40' x 40' design. I used cathedral trusses in place of standard trusses. The only difference was to scarf on an additional 10 feet to form the clerestory windows. The windows are framed in in a conventional manner. The windows were nitrogen filled double paned without E coat. On the opposite side of the windows in the clerestory space is the heat sink wall. The thermal mass i used was scrap drywall. It ended up being one foot thick. this is a tremendous amount of weight, around 30,000 lbs. So a really massive 7 foot deep truss was built into the upper trusses. Basically there were a number of 2 x 10 x 16' plates that were overlapped and acted as upper and lower spar caps. A network of 2 x 4 trusses joined the upper and lower caps. The one problem I had with this design is on the front side of the shop at one of the doors. vertical columns had to be designed to take the load of the trusses. On the back wall this is a straightforward problem, there was 6) 2 x 6 plates that supported the end of the truss. At the door, the problem was that I needed to build and additional redistribution truss to beam the load around the door. I could draw all of this up for you, but a good structural engineer familiar with your local codes could also do it based on my description. If you look at some of the pictures, you will see a dry walling nightmare or dream, depending if you are doing it, or paying someone. Closing out the exposed upper space with the exposed trusses is quite a job. believe it or not, i did all of the work by myself including hoisting the sheets. I would definitely encourage you to copy my shop design, I really miss working in that place. The eaves by the way were 12 feet. One of the modifications I was going to make, but didn't because I moved, was to add a 40 foot x 10 foot green house along the SW wall. I was going to remove the vinyl siding and add a false brick wall. besides allowing me to grow vegetables and flowers year round, the space would double as a passive solar collector called a Trombe wall. I was just going to extend the roof truss 10 feet and re shingle to match the existing roof. its a really good idea to tray and take advantage of existing greenery, to the west of my shop there were 90' maple trees, they had the advantage of offering shade during the summer season when no heat was needed. in the winter, late fall and early spring, they were bare and allowed the sun to collect on my thermal mass. for the rest of the readers who may be confused, here is a link to the shop project. http://robinultralight.blogspot.com/p/other-projects.html if you actually decide to build a shop like mine, you can e-mail me at planebuilder@yahoo.com i would be glad to answer any questions you might have.

Mark Calder
01-02-2012, 06:32 PM
6' 6" is no problem. take a look at this blog in the archive, my friend Mike Lafrance tried out the adjustable rudder pedals http://robinultralight.blogspot.com/2011_10_01_archive.html Mike is 6' 3" and the pedals had another 5 inches of travel. I am 6 foot and for me the pedals are mid adjustment. I asked my Friend Pete (5' 6") to sit in her and there was an addition 5 more inches of rearward travel. Adjustable rudder pedals are required because th pilot can weigh as much as the airplane (in my case)

Mark Calder
01-29-2012, 08:31 PM
My Friend Bill Dale http://www.billdaledesign.com/ (http://www.billdaledesign.com/)came through again with a beautiful Design for my final paint. Unfortunately I haven't been able to do a thing for the last 2 weeks, work and work travel keep getting in the way. I am attaching a picture of my final design, but on my blog, http://robinultralight.blogspot.com/ (http://robinultralight.blogspot.com/) I posted the other options Bill designed. I love the Yellow and Orange designs, but that's really been done before.



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Mark Calder
02-04-2012, 07:20 PM
I just updated my blog http://robinultralight.blogspot.com/ I just added a wing walk to the L/H wing and I also added some photos of a wing retest. Check out my home made load cell!!!

Mark

Dave S
02-05-2012, 07:27 AM
Mark,

I have been following your blog and really enjoy your watching your little bird come too life! I dig the proposed paint job too. I am a little SE of you in Athens- lemme know if you ever need a hand.

Mark Calder
02-05-2012, 01:30 PM
Dave, that's the airport I used for one of my cross countries. If you ever want to come up, just e-mail me at planebuilder@yahoo.com (http://planebuilder@yahoo.com) I will be gone this coming week end however, my friend and I bought an ultralight project. He gets the complete plane, I get the Ballistic parachute.

Mark Calder
02-19-2012, 09:05 PM
I spent a week traveling and driving to Phoenix AZ to but a Mini Max Project so I could get the Ballistic chute.

http://robinultralight.blogspot.com/

Mark Calder
02-23-2012, 08:36 PM
So I was looking for a good used Ballistic Chute, specifically a Second Chantz 550 or 600 soft pack chute. I found a Mini Max Project on Barnstormers in Phoenix for sale with the correct chute. I hate to say what we paid for the project, but it almost exactly equaled our fuel cost there and back. I made a deal with my Friend Ed and we split everything in half, he got the complete project with airframe, new carbon ground adjustable prop, Rotax 377 engine and 10 gallons of certified finish dope. I got the chute.

Today I packed up my Second Chantz Chute and shipped it back to the factory. They walked me through disarming the rocket and detonator. After 19 years that chute would have worked. The igniter was strong and the two rocket capsules made a cool fireworks display when we ignited them.

I have been going through a weight and Balance and asked my Friend Dan Rich to verify the static margin with the chute installed in the turtle deck. The neutral point was calculated to be 37.5% The aft CG with no fuel is 31% so that gives me at least a 12% static margin. Full fuel moved the CG to 22% The pilot is centered on the 25% chord point to reduce trim change with pilot weight variation.

I finished the L/H wing covering. Tomorrow I will rib stitch it. On Saturday I will put the base coat on the fabric. I plan on finishing all of the covered surfaces and then re rig everything. I will add weight to simulate the Chute and do a final weight and balance.

I also need to work with Second Chanz http://www.secondchantz.com/index.html (http://www.secondchantz.com/index.html) to develop the 4 point bridle system. The chute is designed to be mounted on the roll over cage. The bridles will snake over the top of the longerons and run inside the fabric on one of the fabric stand offs. They will loop around the main wing box and the landing gear box. I can just imagine what will happen if that handle ever has to be pulled. You definitely don't want to use this chute for routine landings.

I'm starting to think my Landing gear might not be stiff enough. The fact that I am only mounting the gear at two points and allowing carry thru moment to pass between gears, is causing a rocking motion when the gear is full loaded. This was done on purpose because it allows greater deflection at the wheel and thus greater energy absorption. The gear also might not be stiff enough in the fore aft direction too, I believe I will be adding an additional 1/2" of width on the gear and redesigning the landing gear bulkhead to mount each gear leg at two points similar to a Cessna.

Mark Calder
02-26-2012, 08:46 PM
I started finishing my control surfaces. I outlined everything on my Blog http://robinultralight.blogspot.com/

I am really impressed with how well this House latex paint works and how light it is coming out

Mark Calder
03-03-2012, 02:42 PM
I am really impressed with this method of finishing a plane. I just completed the second coat on all of the wings, horizontal and the control surfaces. I still have paint left in the original one gallon can. I tried to weigh the finished parts to determine the weight per square foot, but the scales I have were not that accurate. I am finishing a one square foot sample and I will compare it to an unfinished sample. I will take the two to work and use some of the precision scales in our test lab. I am waiting on my refurbished parachute to come back from Second Chantz. Once I get that back, I will be able to intall it and finish the fuselage. It wont be long after that!!

Mark

Mark Calder
03-04-2012, 04:25 AM
Here are some pictures of the latex paint being applied. I posted more on my Blog. http://robinultralight.blogspot.com/ (http://robinultralight.blogspot.com/)


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steveinindy
03-04-2012, 05:13 AM
I also need to work with Second Chanz http://www.secondchantz.com/index.html to develop the 4 point bridle system. The chute is designed to be mounted on the roll over cage. The bridles will snake over the top of the longerons and run inside the fabric on one of the fabric stand offs. They will loop around the main wing box and the landing gear box. I can just imagine what will happen if that handle ever has to be pulled. You definitely don't want to use this chute for routine landings.

I thought they had gone out of business several years ago? I always wanted to talk to them about designing something much larger for my non-LSA projects since I'm trying to stay away from solid-fuel rocket based systems as they have the nasty habit of firing upon impact which produces a very good ignition source for spilled fuel (there's a morbid joke in the aviation safety community that the CAPS/BRS is intended more to guarantee a fire so the smoke can guide emergency personnel to the scene of a Cirrus crash than to be a lifesaving device; the other variation I have heard is that the CAPS and wet wing design combo is a "self-destruct mechanism" intended to ensure design flaws aren't detected). If Second Chantz is back in business, I'll definitely have to talk to them.

That said, Mark, if you ever bring the Robin up this way, I call dibs on a chance to fly it. ;)

Dana
03-04-2012, 07:02 AM
Second Chantz went out of business years ago but recently (past couple of years) somebody restarted it... they're making new systems as well as repacking old ones.

steveinindy
03-04-2012, 05:36 PM
Thanks Dana. You made my day!

Mark Calder
03-04-2012, 09:40 PM
One of these days I will be driving thru your neighborhood. My sister lives north of you in Michigan City. I plan on hauling the Robin to Detroit and Oshkosh some day, I will look you up.

John Dunham is the manager of the new Second Chantz. He worked for the original company when they were in business. They will convert pyrotechnic rockets to their AIR system for $1100.

steveinindy
03-05-2012, 02:15 AM
One of these days I will be driving thru your neighborhood. My sister lives north of you in Michigan City. I plan on hauling the Robin to Detroit and Oshkosh some day, I will look you up.

Well, if you ever need a place to rest or duck into because of bad weather, we live about 10 minutes from one airport (KEYE), 20 from KIND and 30 from KTYQ. Our apartment is always available to provide refuge for my EAA compatriots (assuming we are in town, etc).

John Dunham is the manager of the new Second Chantz. He worked for the original company when they were in business. They will convert pyrotechnic rockets to their AIR system for $1100.

Yeah, the major design I'm working on is a bit heavier than what the BRS etc is currently geared towards. However, I figure if the military can drop tanks and other far heavier things out of aircraft, an airframe parachute for a larger GA aircraft should be doable. ;)

Mark Calder
03-11-2012, 09:19 PM
The weather finally broke here in Texas and I rolled out my Robin for its first assembly out doors and its first full weight and balance.

http://robinultralight.blogspot.com/

1707170817101711 The plane weighs 262 lbs with the 7 lbs extra weight prop hub. and with parachute it will weigh 276 under the 284 FAA part 103 weight allowance allowed for a Ballistic chute. With the light prop the empty weight will be 255lbs. The new wings will be at least 30 lbs lighter, that and some other weight improvements will easily allow for brakes and a starter on plans built planes.

Mark Calder
03-24-2012, 03:05 PM
I am spending the week end doing the final paint on the surfaces already covered. I was on a business trip for 4 days so I spent my evenings designing the revised wing. The new wing will be all wood. I have decided not to use the Graphlite rods and straps. I wanted to design a spar that could be assembled separately as a sub assembly, then bonded to a shear web. The problem I ran into is a lack of bond area on the inboard spar. The carbon picks up so much load that it becomes impossible to shear the running load out without interleaving shear ply's. I know I could built that type of design, but I think it is too complicated for the plans builder. I will continue to use them in my Landing gear, there is no issue with bond shear area there. Here are some images of the new spar root,the shear webs are removed for clarity. I have some more pictures on my Blog


http://robinultralight.blogspot.com/
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Mark Calder
03-28-2012, 06:52 AM
I got my Parachute and Riser Straps, The Second Chantz guys really did beautiful job. I plan on installing the risers this week end and then start covering the fuselage. I have been doing the final painting of the wings, I discovered that I actually get a nicer finish using a roller than a spray gun. The addition of Flowtrol to the paint is really beneficial. I substituted ammonia for the windshield wiper fluid for use as a reducer, but other than that, I am sticking with the initial formula. This latex system is definitely the lightest possible way to cover a plane. It appears that the surfaces are actually getting tighter with each application.
Robin Ultralight (http://robinultralight.blogspot.com/)

Mark Calder
04-02-2012, 06:08 AM
I started installing my Ballistic Chute. A few more days of work and I will be able to start covering the fuselage. Still impressed with the use of Latex paint for finish. I updated my Blog with more pictures.

http://robinultralight.blogspot.com/

Mark Calder
04-02-2012, 09:09 PM
I added some more pictures of the Ballistic chute installation on my Blog Robin Ultralight (http://robinultralight.blogspot.com/) Take a look at where I decided to mount the deployment handle. I debated where to put it, see if my logic is correct. I'm open to any suggestions anyone might have.

Mark

Norman Langlois
04-03-2012, 06:28 PM
Mark do you have any numbers on your covering applications per square foot .I recently covered and have painted to 4 cross coats of latex
My totals equal .62 oz per square foot that includes fabric Stewarts system adhesive 1 cross coat of UV Ekofill and 4 cross coats of white exterior latex. Thes numbers reflect the additional weight to the aluminum item .
Have you done better if so what is your comparison if you will.

Mark Calder
04-04-2012, 11:51 AM
Norm, I am not adding that many coats. I have two cross coats of primer which is my UV coat and then two top coats of paint. I'm more concerned with weigh on my prototype than I am UV protection. I plan on stripping the fuselage fabric and rebuilding the wing and landing gear carry through frames. The wings will be new, so I'm not worried about long term UV protection on them. But here is what I ended up with for one wing, the total cover weight with Ekobond is 24 oz. (1.8 oz/yd sq dacron) The paint added a little under 2.5 lbs per wing. So working backward that equates to .015 lbs/ft2. for finish or a total of .024lbs/ft sq

Mark Calder
04-04-2012, 01:03 PM
My totals equal .62 oz per square... Norm are you sure of this number? I think you are off one decimel place. At that weight, one wing of mine would have 101 lbs of covering weight.

Norman Langlois
04-04-2012, 06:32 PM
I thought maybe it would be misunderstood . I am intending to project about 5/8ths of one oz. per square ft
In case I still have it all wrong. The object is half the stabilator raw aluminum weight is 3lbs 8ozs. after covering it weighed 3lbs 12ozs after UV Eko fill it weighed 3lbs 14ozs. after the 4 cross coats of white it weighs 4 lbs 4ozs the square footage is 18.4 surface area top and bottom as near as I can calculate. the white over the charcoal grey cover was poor and so it took 4 cross coats to look good, as the latex sprays poorly with a gun unless thinned to the extreme. 5ozs of paint containing floetroel to 8ozs of fluid .

Mark Calder
04-04-2012, 07:48 PM
Were in the same ballpark Norm. I think Latex is definitly the lightest way to go, keep up the good work, I follow all of your posts.

Mark

Mark Calder
04-07-2012, 01:38 PM
Does anyone know where I can get some seat belt and shoulder harness fittings like these in my pictures? I especially need the shoulder harness fittings like the picture on the left. I bought a conventional seat and shoulder harness from Aircraft Spruce but after I installed them, I realized i needed a crotch belt. The pilot is reclined so much that he will "submarine" under the belts. 17961795

Norman Langlois
04-07-2012, 05:28 PM
Mark I sit here and wish I could help. Mostly I can not see the need. I can not see the situation that would befall a pilot of an U/L that would require that restraint . I must assume the pilot has his feet on the pedals and has some self restraint in that direction. If the nose of the plane comes off then you will lose so much weight you would be falling tail first on your balistic chute I would hope.

Mark Calder
04-07-2012, 08:12 PM
Norm, I have to design for a standard condition. 12 g fwd crash load. In this case the pilot will submarine under the standard seat belts.

Mark Calder
04-09-2012, 08:09 PM
Just updated the Blog to show the progress from the Easter Holiday. http://robinultralight.blogspot.com/

I decided to bite the bullet and buy a second shoulder harness from Aircraft Spruce. I will cut down the shoulder harness and make my two crotch straps.

Mark

Mark Calder
04-15-2012, 05:01 PM
I just updated my Blog again http://robinultralight.blogspot.com/ (http://robinultralight.blogspot.com/)I am almost finished with all of the covering. I also added a series of photos that shows how I went from a 2d paper drawing to a fully molded 3d blister for the rudder cable fair lead

1710517106 I went from this to this in 1 hour


Mark

Mark Calder
05-12-2012, 03:30 PM
I finally started and ran up the engine!!! Smooth!!, this is the smoothest single cylinder engine I have ever seen. I posted a video on the Blog http://robinultralight.blogspot.com/

and another link on the blog to an earlier entry on the theory I used for the engine vibration mounting. Taxi testing could start next week end!!!

Mark Calder
05-15-2012, 12:23 PM
http://www.youtube.com/watch?v=etVNZ5tP2xQ&feature=youtu.be

http://www.youtube.com/watch?v=Scz6I0UFncM&feature=youtu.be

Here is a link to the initial run up and a later run with the cowling. The cowl is getting too hot after the run ups, so I have ordered some insulation and header wrap. I have to wait until I receive it before I continue the run in procedure. The engine cools better with the cowling on than off

Mark Calder
05-17-2012, 08:42 PM
I updated the blog http://robinultralight.blogspot.com/ to show the thermal blankets and header wrap. I plan on breaking in the engine for 4 hours this week end. I bet my neighbors will be thrilled with me by Sunday!!!!

Mark Calder
05-20-2012, 07:30 PM
I just updated the Blog http://robinultralight.blogspot.com/ . I outlined some heating problems I am having and a serious problem with fiberglass fuel tank deterioration due to the ethanol in the fuel. I have a solution for the fuel tank, I am making a new tank and coating it with an automotive epoxy designed to specifically protect against ethanol in the fuel. This is pretty serious, the tank is turing into rubber. I never had this problem 25 years ago with fiberglass tanks on the Wren.

rosiejerryrosie
05-21-2012, 07:02 AM
Folks have been warning about this for years now. I had a friend lose an entire tank of fuel on to his hangar floor when the ethanol ate throught the tank. Another was forced to make an off field landing when the particles from the inside of his tank, created by the action of the ethanol on the fiberglass, clogged his fuel filter. NOT good stuff! Check your fuel lines also to make sure they are not facing the same fate as your fuel tank. There are some folks who strongly advise against using ethanol contaminated fuel in 2 stroke engines - they say that the alcohol has a 'cleaning' affect which robs cylendar walls and other moving parts of lubrication normally provided by the fuel/oil mixture.....

Mark Calder
06-12-2012, 09:40 PM
Finally updated my Blog, I took a long road trip two weekends ago to buy a new trailer so I can haul my baby to the airshows.

http://robinultralight.blogspot.com/

Mark Calder
06-22-2012, 11:35 AM
Had an interesting experience last night. I finally got back to breaking in the engine; I have a new fuel tank that has a protective barrier coating from Eastwood. Anyway, I put about 15 minutes on the engine and when I went to shut her down, it just kept running. I had the cowl off, so I pulled the plug and it still kept running!! There was absolutely no difference in the way it ran or responded to the throttle!!! I finally cut fuel and it quit. I called Leon Massa of Compact radial Engines, the maker of the MZ 34 and he said the engine was dieseling; too much heat was staying in the head. Evidently this has been an issue, because Leon told me he was sending a new improved "cast" head that runs cooler. Its kind of critical in my case because I have a full cowl. Anyway, this cooling issue is the only thing keeping me from my first flight!! I also did a static thrust measurement and I am pulling 210 lbs!! That’s a thrust ratio of .375. Pretty good too, most business jets are around .3. I think I am going to greatly exceed my conservative estimate of 1400 fpm climb rate. The new Bailey 4 stroke seems like its tailor made for this airplane!!

I will be updating the blog with more pictures shortly http://robinultralight.blogspot.com/

Mark Calder
07-02-2012, 07:01 AM
Just a quick update, I have been having engine cooling issues. I ordered a new improved head for the MZ 34. They evidently have had some overheating issues so a new head was designed that increased the fin area. I am also having a run issue with the engine; I can’t get the engine to accept any throttle. I initially thought I was having some Carb issues, because the engine starts on the Prime, but then quickly dies after the prime is consumed. So last night I tore down the engine in anticipation of installing the new head. Turns out every head bolt were less than finger tight!! Exhaust gasses were leaking past the head gasket. Since I only have less than an hour on this engine, I didn’t not re torque the head . I am still trying to break in the engine. I think this may be the reason the engine was dieseling on me. The head was not transferring any of the heat away. Anyway, I'm still waiting for the new head, and if needed, i will be adding additional cooling inlet area for the cowling. I have yet to try a "high" speed taxi. I was hoping to get at least 3 hours ground run on the engine before I reassemble at the airport. I have a feeling that fwd motion will help with the cooling issue once the new head is installed and re torque. I was able to do a static thrust test. This thing pulls like a mule!!! I recorded 210 lbs of static thrust. Once I finally get into the air, this is going to equate to some spectacular climb performance!!!

Eric Page
07-02-2012, 10:57 PM
You might be able to roughly simulate forward motion by placing a box fan in front of the running engine. Before engine start, calibrate the "wind" speed with one of these (http://www.amazon.com/s/ref=pd_lpo_k2_dp_sr_sq_top?ie=UTF8&index=blended&keywords=wind%20speed%20meter&pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B000WHPL14&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0XW64A3YM4SFTYY42H3D#/ref=sr_kk_2?rh=i%3Aaps%2Ck%3Awind+meter&keywords=wind+meter&ie=UTF8&qid=1341291226) and adjust by changing fan speed or moving it closer or farther away.

Mark Calder
07-03-2012, 08:02 PM
Here is a picture of the new head. Evidently Canada isn't a known terrorist country!! http://www.homebuiltairplanes.com/forums/images/smilies/smile%20grin.gifThe poor head wasn't on the no fly list and made it safely to the Great State of Texas!! As you can see there is a huge difference in fin area. I think I am going to assemble everything minus the cowl, spinner and baffling. I need to get another hour on the engine for break in and I obviously want easy access to these head bolts.


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Mark Calder
07-06-2012, 06:31 AM
The intermittent running was caused by a split carb pulse line.However Looks like my Carb pop off pressure still isn't right. I have fuel leaking from the main jet while under pressure from the fuel tank. Most applications do not have a pressure head, so I'm not surprised that there is a leak. I have ordered the Pop off pressure tester from Tillotson. Meanwhile I am spending my "spare" time completing the seat. I have always needed to install a head rest, but as my Friend Ed mentioned today, the pilot is so reclined, that if you just support the head, you will be cranking the head over and choking the pilot. So the seat needed to be reshaped to support the upper shoulders. My seat was made in a two step process, first the tension surface was laid up on a flat foam core and then that bond assembly was forced to the seat contoured substructure. So what I did was remove a 4 inch wide swath of fiberglass to expose the core. I did this on the upper or compression surface. I them clamped the seat to a set of foam form blocks and formed the new contour. This worked quite well because the tension side is still intact and when the seat is formed, the foam will compress. I then bonded a new layer of glass to that surface. by the way, the last ply laid up is peel ply, which just happens to be the same Dacron I covered the plane with.




http://www.homebuiltairplanes.com/forums/attachments/light-stuff-area/18433d1341541934-robin-ultralight-img_0534.jpg (http://www.homebuiltairplanes.com/forums/attachments/light-stuff-area/18433d1341541934-robin-ultralight-img_0534.jpg)

Mark Calder
07-06-2012, 06:42 PM
OK finally the mystery is solved. I took the advise from the aerocorsair web site http://www.aerocorsair.com/index.htm I bought a cooling system tester and converted it to check the pop off pressure of the needle seat. The float needle should have held 8 psi indefinitely. It was leaking down at less than 3 psi. I pulled the whole carb apart and checked all of the gaskets and diaphragms, and yet it still leaked. Finally I tested the needle seat using an alternate port on the carb body and I saw fuel leaking out from the base of the main needle seat. When I pulled the seat out, there was a badly deformed copper gasket. Of course there was no main needle seat copper gasket in my rebuild kit, so I made a new one by hammering out flat a piece of copper tubing and then carefully trimming it to fit. The needle held 8 psi and then popped off at 11 psi, just like it should have. I then started the engine and ran it for another 45 minutes. I'm still working on the seat, and I just finished cutting the slots for the aileron cables and installed the ailerons permanently. There are a few more minor squawks to work off, and then I should be ready for taxi. I still need to run the engine sans the baffling with the cowl, to see if she will cool.

Mark Calder
07-08-2012, 08:56 PM
Latest update to the blog http://robinultralight.blogspot.com/

Mark Calder
08-02-2012, 07:03 PM
I just thought I would post an update while I'm waiting for a carb rebuild kit for the Tillotson HR carb on the MZ 34. I discovered that the needle seat copper gasket was improperly installed causing fuel to leak out the carb inlet. I have been waiting over a month for the gasket to arrive and believe it or not, it actually arrived while I was writing this!! I have spent a great deal of time doing all of the final little jobs that always seem to be an endless task. One of the last final jobs was to have a seat cushion and head rest fabricated. I found a very good upholstery shop right outside the gate of Vought Aircraft in Grand Prairie Texas called "Main Street Upholstery" They did a very good job. I have had 5 people sit in this seat including my friend Pete who is a commercial pilot and commercial glider instructor. Everyone has said that this seat is extremely comfortable. In the photos the shoulder, lap and crotch belts are shown. The red "Tee" handle is the Ballistic chute deployment handle. I should be able to start taxi testing this Sunday. I am updating my blog http://robinultralight.blogspot.com/ to show the seat progress and a side project I have been working on, doing a structural composite repair of a Citabria Cowl. Its outside the scope of this thread, but its a pretty interesting process



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Mark Calder
08-12-2012, 10:12 PM
not quite there yet. I outlined the progress on the latest entry in the blog Robin Ultralight (http://robinultralight.blogspot.com/) I am close!! I have three more jobs to do before I move her to the airport.It should be sometime this week. My friend Pete and Carol have set aside some space in their hanger for me for this coming week. I hope to take it out for final assembly early this week. I am resisting the temptation to rush and hurry, I've been thru these first flights before and its really easy to get so excited, you forget an important detail or two. I will keep every body updated

Mark

Mark Calder
08-13-2012, 07:59 PM
Progress report!!!

Check out the new side window, it works like a charm. I relocated the head rest, it interfered with the canopy swing track. I then bonded the inner track to the fuel door. The fuel door is designed to slide onto the cutout when the canopy is opened. I found a small tear in the bottom fuselage fabric, probably happened when I dropped a screw driver, I need to fix that tomorrow. I will route the Pitot line tomorrow and add the felt grommets. Then I will mount the wings. I will do a complete inspection, ask a few friends to also do the same and then break everything back down , store the hardware and then take her to the Airport, I should be Taxi testing by Thursday evening. If things go well, I will get up very early on Saturday for some "high speed taxi testing. I'm looking for proper engine cooling at this point and loose hardware. If all goes well, Early Sunday will be my first attempt at a lift off. The runway is 600 feet long so I should be able to fly 2/3 the length a foot off the ground. I want to do that at least 3 times before the real first flight. My plan is to use every inch of the run way and get to pattern altitude while over the main run way. That way I have plenty of room to maneuver WHEN the engine finally quits!






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Mark Calder
09-08-2012, 06:17 AM
Just a quick note to let everyone know whats happening with the Robin. I got a nice note from Norm Langlois who was concerned that something might have befallen me!! Well I went to the airport for the first taxi tests and I discovered a problem with the landing gear. My design , using a spruce wood core and carbon pultruded flats started to crush under the clamp stresses and taxi stresses. As a result the gear started to slide outward. We noticed it immediately and stopped all taxi testing. I took the Robin back to my shop and pulled the gear. Bottom line is, I ordered a brand new Aluminum spring gear from Grove Manufacturing. I am not giving up on the idea I had for this gear, but a one piece aluminum gear is a known entity and represents one less variable. I am making modifications for the new gear to the Fuselage. I will be back in air in a few weeks.
Last weekend I had the privilege of being asked to speak at the ESA's (Experimental Soaring Society) western conference in Tehachapi California. I really had a great time and I received a lot of comments on the Robin. The ESA is the Homebuilding division of the SSA (Soaring Society of America) as such they are just like the folks at the EAA except engine-less.

Mark Calder
09-14-2012, 01:03 PM
hey if you guys are needing some epoxy Primer, I put some inexpensive primer for sale on E-Bay. Water Based Epoxy Primer (Yellow) | eBay (http://www.ebay.com/itm/261097937205?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649) This is surplus from Vought aircraft. Its the basic primer used on all Boeing aircraft. I am listing it fo $35/kit (2 gallons) , but if you bid $25 I will accept it. This is really high tech stuff, its epoxy Polyamide and water based. Its designed for electrostatic spraying, but it can also be sprayed with conventional guns. The primer has expired so its not usable for a certified aircraft. I have had a kit that was out of date by 4 years and as long as the can is un opened, its still good. 2 years ago I had a bunch of this primer and sold it to a guy in Bath Maine who was using it on long lining Swordfish boats. He was buying it from Deft for $300 kit. So buy some of my primer so I can get my N/C router!!!! LOL!!!

Norman Langlois
10-16-2012, 04:57 PM
Mark its been a long time since your last post.Have you made any progress toward test flights?

Mark Calder
10-17-2012, 11:44 AM
Mark its been a long time since your last post.Have you made any progress toward test flights?


Thanks Norm for your concern. yes, i am finally making some progress. My new landing gear came in from Grove Aviation yesterday. I'm still waiting for the radius block clamps, so I can finish the gear installation. I have uncovered the fuselage and rebuilt the local gear attach frames and bulkheads. I decided to add the gear external to the longerons, rather than though the fuselage as the previous gear was installed. I will redesign the final gear installation to clean it up a bit, but this is a very clean redesign for the existing structure. Here is a picture of the gear sitting in place:

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Mark Calder
10-30-2012, 08:02 PM
I updated my blog Robin Ultralight (http://robinultralight.blogspot.com/) to show the latest update for my new gear redesign. A friend of mine bought a Tiafun Motor glider that had a nose gear collapse . He bought id off the AIG insurance web site. He lives in New Jersey and if he can get his flight out on Thursday we are going to drive to Moriarty New Mexico this Friday to pick it up. He got a hell of a deal and I will post some pictures when we get it.

Mark Calder
12-02-2012, 08:04 PM
Well I'm getting closer to going back to the airport!!!

There is a nice write up from Dean Sigler on page 64 of the January edition of Kitplanes magazine. I met Dean at the 2012 Experimental Soaring Societies western conference in Tehachapi Ca over the labor day week end.

I just updated my blog Robin Ultralight (http://robinultralight.blogspot.com/) I am showing the new gear and the additions of the adapted go Kart brakes.

EAAStan
02-15-2013, 11:32 AM
. . . He bought id off the AIG insurance web site. He lives in New Jersey and if he can get his flight out on Thursday we are going to drive to Moriarty New Mexico this Friday to pick it up. He got a hell of a deal and I will post some pictures when we get it. I tried finding the site but could not. Would you please give any details you have regarding the AIG site or any other way to find out about totaled aircraft available for purchase from insurance companies. Thanks so much. Stan S

EAAStan
02-15-2013, 12:33 PM
Never mind, I found the site. All the best, SS

Norman Langlois
04-20-2013, 04:46 PM
Hello Mark
Are you still active ? And moving your project along. It's been a long winter .Thought maybe I would see some update with warmer climate where you are. I still have 4 weeks or so to go. I'm working on transport and handling now . Aircraft modifications during the 4th week and then it's back to the sky for me.