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Thread: Robin Ultralight

  1. #21

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    Oct 2011
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    Second Chantz Ballistic Chute

    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 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.
    Last edited by Mark Calder; 02-23-2012 at 08:39 PM.

  2. #22

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    Oct 2011
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    Latex Paint Covering Process

    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

  3. #23

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    Oct 2011
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    Latex Paint Covering Process-2

    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

  4. #24

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    Oct 2011
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    Latex Paint Covering Process-3

    Here are some pictures of the latex paint being applied. I posted more on my Blog. http://robinultralight.blogspot.com/


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  5. #25
    steveinindy's Avatar
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    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.
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  6. #26
    Dana's Avatar
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    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.

  7. #27
    steveinindy's Avatar
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    Thanks Dana. You made my day!
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  8. #28

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    Oct 2011
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    Midlothian Texas
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    Steveinindy

    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.

  9. #29
    steveinindy's Avatar
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    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.
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  10. #30

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    Weight and Balance

    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/

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Size:  91.1 KB 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.
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