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George in Langley BC

Well Known Member
Hi Builders

I am just starting on the gear leg fairings on my 7A and as I was laying in bed thinking about the trailing edge hinges the question popped into my head, whats wrong with using Velcro?

Advantages are lighter and simpler, only worry is how long the Velcro glue will stay attached to the epoxy fairing.

Anyone have any comments on how well industrial quality Velcro will stay attached in a very small load application??
 
George in Langley BC said:
Hi Builders

I am just starting on the gear leg fairings on my 7A and as I was laying in bed thinking about the trailing edge hinges the question popped into my head, whats wrong with using Velcro?

Advantages are lighter and simpler, only worry is how long the Velcro glue will stay attached to the epoxy fairing.

Anyone have any comments on how well industrial quality Velcro will stay attached in a very small load application??
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Hey George... too exicted about Santa arriving?

Here's the stuff you need 3M Dual Lock. They even offer types that can be riveted in place.

The only limitation is the lower temperature limit. You'll need to pore through the datasheet to see if this applies in the static application, or only applies if you are pulling them apart.

Merry Christmas, Chocks!

Vern
 
Dimensions

Maybe you have thought this through, but it seems to me that it would be much harder to find the exact position for the velcro that will bring the trailing edges of the leg fairings snugly together and still not put too much pressure on the velcro. It will surely be lighter! I would like to know how this works out, too. Thanks.
 
Flexing

I think the biggest issue would be the velcro or the other stuff mentioned, will not provide the necessary stiffness to the trailing edge of the fairing. You don't want the fairing flexing or you'll never be in trim. The hinge system is quite quick to build and very efficient.

The 3M stuff mentioned has incredible grabbing power. So much so I think you might have trouble getting the thing undone!!!
 
No, bad idea, why?

OK someone has to say it. :eek: Lets stop beating around the bush. No. Bad idea. Why?

"Build it per plans" :D

If you follow the mantra, "Build it per plans", chance is you will fly sooner, lighter, cheaper and it work well. The piano hinge or bonding it on perminatly is the time honored tradition.

Go it alone, chance is you'll add time, cost and problems.

You really don't need a removable gear leg faring any way. How many times has the gear leg fairing come off in 1000 hours? zero.

I'm going to guess velco is not cheap. Also you want to have the gear leg TE's locked in postion, both edges flush and aligned. If it comes undone it could cause some grief and vibration. No. Bad idea. Why? :D Sorry someone had to say it.
 
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Um-mm wildebeest

KTM520guy said:
Don't be like the herd, walk your own path.
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Ha ha ha, well normally I'd agree, but in aviation walking your own path is like the lone straggler wildebeest / antelope in the herd, it gets eaten by the lion. :eek: What kind of dent would the gear leg fairing make in the tail? :rolleyes:
 
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The original poster gets a "A" from me for thinking outside the box. Myself, I'll use the piano hinge even though I hate that stuff. I don't think velcro would be totaly bad. If you use upper and lower fairings,they will hold the gear leg fairing in place. Don't forget, a lot of times there is a hose clamp at the top of the fairing. I'm pretty sure it's not going anywhere.

:)
 
KTM520guy said:
Don't forget, a lot of times there is a hose clamp at the top of the fairing. I'm pretty sure it's not going anywhere.

:)
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The fiberglass under my hose clamp broke the first flight it made. :eek:

Kent
 
kentb said:
The fiberglass under my hose clamp broke the first flight it made. :eek:

Kent
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I'm working on that part right now. Did you lay any additional glass under the fiberglass tab?
 
Actually, the plans call for additional layers of fiberglass under the tabs to reinforce them.
I'd stick with the plans, it's less trouble to do it right the first time rather than to do it over again.
 
Whats wrong with using Velcro

I am the origional poster this subject and subsequently did some testing with Velcro on the scrap fairing pieces. I ended up using hinges as per plans. Extra three hours work and 6 ounces weight.

Because of the thickness of the Velcro it needs to be set back about 5/8 inch from the fairing trailing edge, this puts the Velcro on the angle portion of the gear leg fairing resulting in the Velcro only being attached on the aft 1/4 inch.
This gave a reasonable attachment and was probably strong enough but I ended up with about a 1/16th gap on the fairing trailing edges and judged that not acceptable.

With the hinges I ended up with one fairing nice and tight on the trailing edge and the other with about 1/16 inch gap requiring heating and reforming the edge.
 
I am facing this situation currently. I am very tempted to glass the trailing edges together since it is unlikely that I will need to access the gear leg again. If I did need to access the leg, I would have to split the seam and repair the paint...Am I missing something here?
 
Praise the Creative, be critical of radical airframe ideas

tinman said:
I am facing this situation currently. I am very tempted to glass the trailing edges together since it is unlikely that I will need to access the gear leg again. If I did need to access the leg, I would have to split the seam and repair the paint...Am I missing something here?
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That is a very acceptable method. It saves cost and weight. It's used by the Harmon Rocket builders and Team Rocket (F1).

Hey it does not hurt to ask. There are no stupid ideas. That is the point of the community, to vent ideas. However I have to call it as I see it, and just giving my opinion.

I have learned a lot and stole my share of good ideas from others on this and other online RV list's. There are better ways sometime, no doubt. Yes we should try to make it better, but after 30 years of RV's, most, not all, of the alternate "airframe" ideas amd ways of doing things have been explored. I would recommend being very conservative with the basic airframe changes. Unless you are an engineer or get Van's Aircraft concurrence, I'd proceed with extreme caution. Again, rule #1, follow the plans, it will save you from yourself. Trust me. :D

Fairings have KILLED! Got your attention? Well its true a tail intersection fairing came loose and the part that hangs down behind the torque tube and caused a jam. In another case, which also cause an elevator jam, the fixed leading edge horizontal stab tip faring jammed with the elevator faring due to gaps being too small. FOLLOW THE PLANS!

A good sources of "alternate ways" can be found in old RVators (the commercial compilation "X years of the RVator" is pretty good) and other sites, the biggest being Matronics.

Again for all the "yea go your own way" guys, trust me. I was an out of box thinker, once; did it anyway but the plan's way. Time and time again I made more work, and even when the results where good, I still often wished I had just stuck to the plans. Trust me. :D Save your creative genius for the instrument panel layout, fancy paint job, fuzzy dice and alligator seat covers.

Cheers all you "true men of genius". :D (one of my favorite commercials) I ain't hating the creative folks, but I have to call poo-poo on an idea as I see it. Velcro should not be used for any AIRFRAME structure, including secondary structure like fairings. PS the single hose clamp and glass tab will nor keep the fairing in place at 200 mph if the trailing edge comes unzipped in my opinion. I think the transition "cuffs" top and bottom may retain it? Who knows but I don't want to find out.
 
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