KR-2 Buy

[Trevor Norman]

Greetings,

I purchased a KR-2 aircraft while I was on deployment.

I haven't been home yet to see what I purchased, but I'm looking for some guidance on it.

From what I understand, the aircraft is mostly finished, I need to do some work on the bottom of the fuselage, and a little bit of repairs on one of the wings.

First, how does one inspect the quality of work for carbon fiber and fiberglass? Is there something on the inside that I can look for with regards to seams and repairs?

Next, the aircraft came with the engine. It's a RevMaster 2100, but there is no manual. It only has a handful of hours on it, and the sales staff at RevMaster haven't gotten back to me with regards to the maintenance manual. I assume that I'll need to take it apart, clean it, and inspect for any sort of corrosion (the engine was hung on an engine stand, and in SW California so rust, and cylinders are my big concerns).

When all said and done, the previous owner started installing some of the electrical for some lights and such, and I have an order placed from Aircraft Spruce for some lights, a new altimeter and a few other things to finish the project and get it flying. So, what is my process of running wires down the wings, that I assume are full of foam?

I am also planning to remove the single wing fuel tank (why they only installed one wing tank puzzles me) and install another set of wing tanks that will give me a higher capacity for long cross countries (goal is 800 miles).

Speaking of wings, I'm deciding to install Vortex Generators on the wings, anyone have any good/real life reports for VG's?

I am looking to make the aircraft legal for night trips. The electric won't be a problem, I have lights on order, but I'm not so sure about setting up the electrical, and how to make a system that is safe.

After all that is complete, I'm looking at the process for getting up in the air. Anyone have a manual for flight testing of high speed aircraft? What paces did you put your aircraft through? How did you measure your weight and balance compared to the original design? Your max gross? Usable load? Speeds?

I'm sure I'll have many more questions, but first I'd like to see what you guys suggest before I get my hands dirty.

Thanks,

Trevor

[martymayes]

Typically a KR-2 has a wooden structure with foam and fiberglass providing the shape. That's if it is built to plans. There are some vendors like nVAero that supply a number of components for the KR-2 but I'm pretty sure the wood structure does all the load carrying.

So with that, it's inspect like you would inspect any wooden airplane. Since the plane is unfinished, ensure the building records are included so you can show the FAA it meets the criteria for amateur-built.

KR-2 builder groups are easy to find on the internet like http://www.krnet.org/ so they can probably offer a lot of building advice on the specifics.

[cub builder]

Trevor;

Join the KRNet email forum. There's a lot of good and bad advice on there as well as some interesting discussions. You'll figure out who knows what they are talking about in fairly short order.

Joe Horvath at Revmaster will help you out with your engine. He's a good guy. Generally speaking, plan to adjust valves at every oil change (25 hrs) and the Revmaster will give you reasonably good service.

As designed, the KR-2 isn't something you would typically want to be flying at night. It lacks pitch stability and is very touchy in pitch. You'll see a number of them modified with larger tails, which really helps address the pitch stability and the lack of feel in the elevator. Get it configured right and you'll really enjoy your KR. I have well over 1000 hrs in mine.

As previously mentioned, inspect as a wooden aircraft. Look for damage to the wood, bad or failing joints, neatness of the construction with the glue joints. That will tell you a lot about what you have bought and what you are going to need/want to do before it flies.

There are some very good flight test manuals available for downloading; one written specifically for the KR series aircraft. Gross weight, useful load, speeds, etc, are all over the map depending on engine/wing/avionics/fuel tank configurations. There is a spreadsheet available on line showing many of them. Do some perusing of KRNet.org, and join the KR email group as that's the place to ask many of these questions.

-Cub Builder

[martymayes]

I have well over 1000 hrs in mine.

Have you and your plane ever been featured in an aviation magazine?

[cub builder]

Have you and your plane ever been featured in an aviation magazine?

No.

[Bob H]

Inspection of cured composite laminates looks for resin starvation, delaminations and disbonds from adjacent structure. Visual exam usually shows starvation as dry material. Delams show as ply separations and disbonds as bulk separations between laminate and structure. A simple coin tap test can distinguish between sound laminates and those with defects.

[Richard Warner]

Trevor, You might find this discussion on the KR2's safety record interesting.
http://www.homebuiltairplanes.com/forums/aircraft-design-aerodynamics-new-technology/16362-zenith-kr2s-sonerai-safety-record-comparison-print.html

[cub builder]

Trevor, You might find this discussion on the KR2's safety record interesting.

As you point out, the KR doesn't have a sterling accident record. But Trevor already owns one, so the question becomes, what to do to improve the safety of his aircraft? I'll expand a bit on paragraph 3 of my post from 1/20.

As designed the KR-2 has issues with pitch instability and lack of any feedback (or feel in the stick) in pitch. That is a primary contributor to the safety record of the KR aircraft, although the use of alternative engines is another strong causal factor. The -2S model went a long ways towards fixing the stability issue with a larger tail and extended fuselage. My KR is a -2 with an extended fuselage. I flew it for 500 hrs with original KR-2 tiny tail on it. At 500 hours, I redesigned a significantly larger tail and added flaps to the aircraft. That made a huge difference in the handling and stability characteristics of the aircraft and made it as easy to fly as any other aircraft of similar performance. Additionally, I don't mind experimenting, but I tend to stay away from alternative powerplants. That's just my personal preference for the way I fly.

-Cub Builder

[flyrgreen]

Trevor, a note about installing lights & such: the stator/alternator on the VW conversions is not a robust power producer. I recommend you use LED lighting wherever you can. Especially strobes & landing lights. LEDs use much less power.

The factory VW cases have some stress-cracking issues: The exterior flashing seams should all be shaved smooth, particularly the vertical one on the passenger side near the front, just below the oil pressure outlet. And keep your prop & spinner well balanced!

For non-technical questions @ Revmaster (like can you send me a maintenance manual), Roberta in the front office will get back to you better.

-- KR2/Revmaster owner

[Trevor Norman]

Thanks for the replies...I am sorry I haven't responded sooner, my current status of being away has really hindered me asking questions.
I plan on being back in the states next week, and there I will have some leave and R&R to use up.
As for the safety record of the aircraft, I understand there are concerns about the safety of the aircraft, but I plan on mitigating some of the issues, for example the fuel system issue (which was one of the more common issues that caused forced landings, and so on.
The aircraft right now is in a storage facility, so I plan on inspecting it within the week I return and decide what needs to be completed.
As for lights, I have a set of lights picked out, I'm going all LED lights. I'm going to use the X-Pak nav/strobe combo and an LED red beacon for the top of the rudder. It's the largest space savings that I could find.
Next, I' getting rid of the steam gauges for the existing six-pack and going digital. Now, correct me if I'm wrong, if the aircraft is not a certified aircraft, I can use an EFIS program on a tablet that gives altitude, speed, pitch, and so on to give me my basic VFR pack?
The pitch control is not really a huge issue for me.
Has anyone completed some long cross country flights with the aircraft? I'm looking at mid-summer to going from Minneapolis to Richmond, weather permitting for some business I have out there, and I know between my travels, flying my aircraft would be cheaper.
When I get home, I'll post some photos in hopes that everyone can give me ideas.
Thanks for your time!

[Dana]

Legally, yes, you can use a tablet EFIS for a primary display. Personally, I wouldn't do it without a backup for the most important functions, tablets still lock up occasionally.

Dana

[Marc Zeitlin]

Next, I' getting rid of the steam gauges for the existing six-pack and going digital. Now, correct me if I'm wrong, if the aircraft is not a certified aircraft, I can use an EFIS program on a tablet that gives altitude, speed, pitch, and so on to give me my basic VFR pack?So this is an interesting question, and brings up a quirk of most E/AB Op-Limits. They do NOT specify what instruments are required for Day VFR flight - in fact, LEGALLY, NO instruments are REQUIRED for Day VFR flight. Read your OL's - they WILL say that you need to conform to 91.205 for Night and/or IFR flight, but they say nothing about what's needed for Day VFR.

Now, on a new build, no DAR in their right mind would give an AC to an E/AB aircraft that had no instruments in the panel and I've never heard of anyone trying it (and they'd probably get you on a 91.13 during a ramp check if they saw no instruments in the panel) if you removed them after approval, but it's an interesting thought experiment.

With respect to your question, then, for Day VFR, sure - the tablet would be legal, since there are no requirements in the OL's. But you said you're installing lights, implying that you want to fly at night. As soon as you do that, you then need to comply with 91.205 and you will then need an ADAHRS (such as the Levil-AW that has pitot/static input) in order to have a real altimeter and airspeed indicator on the tablet display - GPS groundspeed is not sufficient. You will also need some sort of compass or magnetometer (which the Levil-AW has), and a bunch of engine instruments, which the tablet will not support.

So, I think that with the appropriate additional hardware and software, yeah - a tablet EFIS would be legal for night flight. I'd seriously think about a dedicated unit, though - something like the GRT Mini - prices have come WAY down, and it's far less likely to have lag and crap out on you (and you can incorporate a real engine monitor into it as well, which all aircraft flying cross-country should have at this point, given the capabilities and prices). For the price of the Levil-AW and tablet, you can get a nice dedicated unit.

My $0.02.

[Trevor Norman]

Thanks for the info. I do not think that I will flying simply during daytime.
As someone who is new to this whole thing, what goes into a pitot static system? I know you need a pitot tube, and a vent, and some tubing, but will I require a pump of some sorts?
I have attached a photo of the panel as it sits right now. I intend on making a different one so I can have my personal layout.
It currently has steam gauges, but I am not sure if the altimeter is with the box of "stuff" that I received, or if I'll need to purchase one from Aircraft Spruce.
Now, for my next question, how do I develop a panel? I have a transponder, radio, instruments and switches, but how do I make it look professional with its layout, and how do I label everything to make it look good and functional?
http://eaaforums.org/attachment.php?attachmentid=4496&stc=1

[Dana]

The pitot tube goes to the airspeed indicator. The other connection on the ASI goes to the static source, which may be a port on the side of the aircraft, but is often just left open behind the panel or inside a wing, which may be less accurate but may be good enough. The altimeter and rate of climb also go to the static port (or again, just left open). No pump required. Gyro instruments (like your turn and bank or an artificial horizon or directional gyro), if not electric powered, require suction, which can come from a vacuum pump or from a vacuum venturi on the outside of the aircraft.

How you lay out your panel is personal preference, but generally, flight instruments are grouped together, engine instruments are grouped together, and and radio stuff is together. My plane has the compass on top center, three 3-1/8" gauges (ASI, altimeter, turn&bank, tach) in a row, and four 2" engine instruments (EGT, CHT, oil pressure, oil temp) in a row below that. Fuel gauge is a sight tube on the LH side of the panel. Only one switch (magneto), and a handheld radio on a clip on the RH side of the panel.

Dana

[Trevor Norman]

Thanks for the info. I think in that case, I'll just remove the Turn Coordinator, and that should give me enough room to install a panel mounted bracket for my iPad mini or iPhone for a backup Artificial Horizon.
Below is the photo of what I planned my panel to look like to some degree. It's not really up to scale, but I think it could fit pretty well.
http://eaaforums.org/attachment.php?attachmentid=4497&stc=1

[crusty old aviator]

Don't get too clever, Trevor, or your lil' gal might get too fat to fly. What was her empty weight when she was flying? Ken Rand designed her to weigh about 440 pounds, with a GW of 800 pounds. You should check the weight and balance calculations the original builder performed...you may be back here asking for advice on how to give her the Richard Simmons treatment!
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[flyrgreen]

Crusty is correct that there have been more than a few KR's built too heavy to fly, or fly safely. However, many are flying that weigh in the 550-600 lb. empty range. Mine is one--- weighs 600. I have had several flights with 300 lbs of humans & 60 lbs of fuel, with no problem. Climbs 1000 fpm, 100 mph, at that weight. The CG on my KR is very near the aft limit with 2 people & low fuel, but within spec. This is with a 2180cc 75hp engine. If yours has a 1600 or 1800cc engine, you would want that bird to be nearer the 450-500 range.