Engine run wings folded?

[LSaupe 123]

I assume the answer is no, but has anyone done an engine run with the wings folded (low to medium power)?

 

Want to do a quick check out (actually see if she starts and runs).  Wasn't sure if doing this folded was a real concern or not.

 

 

[EDMO 1078]

I have done it once with the nose tank - With wing tanks, you are only going to get gas from the header tank-maybe?

If you have the front and rear travel braces, I think it would be better to install them first.

You can get a lot of shaking if idle is set too low...

Put a strong rope, cable or chain on the tail and tie it to a tree or vehicle - runaway props are no fun!

EdMO

Edited 2 Aug 2015 by Ed In Missouri

[Av8r3400 1179]

I would be concerned with inflating and damaging the wing fabric first and foremost.

[LSaupe 123]

Front and rear travel braces?  I have a set on the rear, but where do the forward ones attach?

Edited 2 Aug 2015 by LSaupe

[dholly 718]

Back braces simply keep the wings from unfolding, front braces support the wing weight when folded. They attach between the hole in the lift strut to fuselage bracket and the front spar pin holes. Mandatory for trailering, particularly with fuel left in the wing tanks, and easily made out of standard electrical conduit. Don't seem to have a good close up but these pics will give you the right idea.

[edit] As for your original question, I ran up my folded KF3 once. Nothing broke but never again.

Edited 2 Aug 2015 by dholly

[EDMO 1078]

I would rather use 1020 or 4130 tubes, round or square, instead of conduit - Just my preference, and it welds better.

Nice photo, as usual, Doug.

EdMO

You can always tape some cardboard or stuff something in the root rib holes if you are worried about fabric, but I have pulled one at 65 mph on a trailer with no ill effects on fabric with the holes open.  Probably better to keep bugs and dust out tho...

Edited 2 Aug 2015 by Ed In Missouri

[dholly 718]

No welding necessary with conduit Ed, simply flatten the ends in a vise and bend slightly to the proper angle, then drill the bolt holes. I did have to cut a small 'V' notch in the conduit to clear the lower longeron near the bottom bolt. Took maybe 5 mins. tops to make both, easy peasy!

[EDMO 1078]

Doug, where do yours attach to spar - underneath?  The one I had actually went inside spar like the fuselage tubes and the wing bolt held it.  Maybe overkill

EdMO

Edited 2 Aug 2015 by Ed In Missouri

[dholly 718]

Correct Ed, goes underneath with a short bolt and wing nut thru lower spar pin hole from inside of spar. I got the welded braces with bushings with my Avid and, to be honest, I prefer the conduit because there is no chance of imparting twisting force or possibly tweaking the spar end. The conduit is plenty strong.

[1avidflyer 1983]

Just my opinion, but if you have the plane tied off, and don't run at full throttle much it shouldn't hurt anything. Here are some pics of wing brace tubes in place. The black tube I have my hand on. I don't remember on the Kitfox, but on an Avid the fabric is glued down pretty good to the tank, and it would be hard for the fabric to start to blow off. No point in pushing it a lot though. Jim Chuk

[LSaupe 123]

Great info as usual, many thanks!

[tcj 150]

I run mine with the wings folded sitting on the trailer.  Make some cardboard pieces to fit in the wing root rib end openings to keep the prop wash out of the wings.  I have run mine up to full throttle.

 

The bottom of the wing brace will fit if you make a little bend in it there.

[KFfan 151]

I had the oppotunity to drag my KF2 outside a week ago to test run after installing the new float in the aft carb. 1st time I have run it. Deployed the wings and found I hat to repair the right spar attachment reinforcement! I have no idea how anyone managed to deform it. Wings deployed, chained to my truck, tire chocks and full brakes. (didn't want any surprises) Engine ran well. Shook like a off balance washing machine on spin cycle at 1800 by KF tach. Smooth at 2200. No fuel dumping or coolant leaks. WooHoo! Was pretty surprised when at 5K I felt the tail come up. I think because the elevator was deflected?

 

Lou

[LSaupe 123]

Perfect!  Thanks TCJ!