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  #1  
Old 09-22-2009, 10:12 AM
diamond diamond is online now
 
Join Date: Sep 2009
Location: Rochester, MN
Posts: 710
Default retractable gear on RVs?

Sorry if this is dumb, but I'm at the bottom of the learning curve. With all the mods I read about for RVs, is there a mod for retractable landing gear, especially for the taildragger -7 or -9? If so, other than looking cool in the air, what is the upside and downside of doing this? Thanks
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  #2  
Old 09-22-2009, 10:22 AM
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Kahuna Kahuna is offline
 
Join Date: Dec 2004
Location: Gold Hill, NC25
Posts: 2,408
Default

Recommend you use the search function.
Hint:
Search, advanced, retract, search titles only, Wallah

You can do the same for retractable, or other terms of interest.
Start with titles only, move on to posts if you dont like what you get.
You will find much material.
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  #3  
Old 09-22-2009, 10:33 AM
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Steve A Steve A is offline
 
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Posts: 211
Default Retractable Gear in an RV

Several years ago Kitplanes (or EAA Sport Aviation mag) had a feature on a guy in Germany adding retractable gear to an RV. He had both a retractable and fixed and after a ton of work, the retractable gear added about 2-3 knots to the total speed. The article was interesting to read and the technical obstacles overcome were formitable, but bottom line is the fixed gear is very efficient with the proper fairings.

S S Anderson
RV 7A Flying
Await kid graduation to buy more avgas
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  #4  
Old 09-22-2009, 11:18 AM
David-aviator David-aviator is offline
 
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Location: Chesterfield, Missouri
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Quote:
Originally Posted by Steve A View Post
Several years ago Kitplanes (or EAA Sport Aviation mag) had a feature on a guy in Germany adding retractable gear to an RV. He had both a retractable and fixed and after a ton of work, the retractable gear added about 2-3 knots to the total speed. The article was interesting to read and the technical obstacles overcome were formitable, but bottom line is the fixed gear is very efficient with the proper fairings.

S S Anderson
RV 7A Flying
Await kid graduation to buy more avgas
Burt Rutan determined the same thing many years ago with his canard airplanes. It simply is not worth the complexity and cost to do it. If we flew at 400 knots it would be another matter entirely, but not at the speeds we fly.

The cost of maintaining the retraction system is much over the years. Every annual the certified retracts have to be swung plus insurance premiums are always higher as there is some truth to the saying there are those who have and those who will - land gear up.

The only thing that prevents it in big airplanes is a checklist, another crew member reading it, and the death penalty if you don't.
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  #5  
Old 09-22-2009, 11:46 PM
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Shockwave Shockwave is offline
 
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Location: Ankeny, Iowa
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Upside is 2-3kts, less fiberglass work which some seem to hate with a passion, and easier tire inspections. Short of a major new finding in cooling drag, this may be one of the last places to pick up knots after the aft cowling fairing.

Downside is designing and engineering your own solution, as there aren't any ready-made mods that I'm aware of. You might be able to kit-bash from another plane, but you'll still have to incorporate that design in and really test it out.

I would think it'd be easier than the stretch 6. If you want it bad enough, it's not insurmountable. It would be a big undertaking however.
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  #6  
Old 09-23-2009, 12:41 AM
schimms schimms is offline
 
Join Date: Sep 2009
Location: Germany
Posts: 3
Default There you are

Pics taken on the 2nd RV meeting in Damme, Germany. I hope the owner doesn`t mind me posting these.


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  #7  
Old 09-23-2009, 06:16 AM
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pierre smith pierre smith is offline
 
Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,885
Default Retractable tailwheel too...

Very well done example but I'm guessing an additional 250 lbs or more. I also read that this airplane cruises right at VNE, not just 2-3 knots faster.

Regards,
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  #8  
Old 09-23-2009, 08:56 AM
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airguy airguy is offline
 
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Location: Garden City, Tx
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Quote:
Originally Posted by pierre smith View Post
Very well done example but I'm guessing an additional 250 lbs or more. I also read that this airplane cruises right at VNE, not just 2-3 knots faster.

Regards,
Possibly - but that's a function of power as well - and with that 3-blade prop the obvious question is what engine is installed?
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  #9  
Old 09-23-2009, 09:01 AM
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Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
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Quote:
Originally Posted by Shockwave View Post
Downside is designing and engineering your own solution, as there aren't any ready-made mods that I'm aware of. You might be able to kit-bash from another plane, but you'll still have to incorporate that design in and really test it out.
Another downside not mentioned is the placement of the fuel tanks farther outboard.
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  #10  
Old 09-23-2009, 09:05 AM
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DanH DanH is offline
 
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Location: 08A
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That 'ole boy has been tinkering with a lot of things...for example, check out the cooling air exit area and exhaust system.
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