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running engine without wings on

david.perl

Well Known Member
Im trying to do as much of my assembly before taking the plane to the flying field foir final assembly.

I asked my inspector if the engine can be tested before the wings are attached, he said sure, no probs. I remember seeing a youtube clip of a plane shake itself to death in a similar scenario. He said if there was that much vibration with or without wings on, that plane had major issues.

any thoughts or experiences?
 
I don't know any technical about this however, my opinion is the wings would help dampen engine, torque and surges. I would not do it, our rv are already light for engines sizes used.

Bird
 
Do not!

Somewhere it is written or Vans told it:

Do not run engine without the wings installed and without the baggage compartment bulkhead closed.

The wings will dampen the pulses from the enginge during the start/stop shaking, the baggage bulkhead is part of the fueselage integrity.

There are videos and pictures of builder who dont follow this and there plane did not fall apart. But if the designer say you should not ... it is wise to do so.
 
Don't do it.

Not a good plan. The wings provide balance and torsional stability. Also, you'll have to rig a fuel system that is probably not the safest. I'm not sure why you would need to run the engine without the complete airframe.

A friend ran his 7 without wings. When it started it danced on the wheels until it smoothed out. It was fine until he shut down. The fuselage shook badly and it looked like the canopy was going to come off.

He had no real reason to run the engine, just that he wanted to. He almost paid a very expensive price.
 
Gents, I've seen an RV-6A run without wings, and it did just fine. Don't recall if the HS was on it or not. I can check, if it really matters.
 
Hi David

I asked my inspector if the engine can be tested before the wings are attached
Are you really saying the engine needs "testing" i.e. it has never been run? I presume you had it built by Lycoming / AeroSport / CFS who whoever - did they not test run it?

If what you mean is the engine has been test run already, but you want to check the installation functions, then I would suggest you leave it as late as possible. One of the main "tests" anyway are fuel flow functionality checks from the fuel tanks, which sort of need the wings installed :)

A new engine should not be run much at all prior flying due cooling etc. IMHO.
 
Andy is correct.

A ground run for leak checks and system/taxi brake checks is all it needs. Anything else is not helping and in some cases can be hindering.
 
I personally did it with my 8A. I also heard all the wives tails and shouldn't do that and all the voodoo and planes falling over and Nada nothing! I did not know before hand of all the stories. Plane was stable and did not vibrate in excess.:D Had prop on and no tail. I think if you need to do some checks and tie it down and chock it and are careful and not rev it or chop the throttle you'll be fine. But as a safety reminder your mileage may very and it's up to the individual to take that chance just like getting in the plane or car or whatever it is, it's your bacon!:eek:
Scott
8A
 
It is not wives tails.
Van's has recommended against it because of actual instances of damage to airplanes from doing, and because of that knowledge, no airplane built at Van's or connected to someone that works there has ever had an engine test run without the wings attached (Van himself wont do it).
There has also been instances of people doing it (either because they didn't know before hand or they believed it was just wives tails?) with no problems reported. The problem seems to be related to the rotational inertia damping provided by the wings.
Since there are known instances of good and bad, and the exact details of why some times it worked fine and other times it didn't, and since there is really no particular benefit, the recommendation is Don't Do It.
 
I personally did it with my 8A. I also heard all the wives tails and shouldn't do that and all the voodoo and planes falling over and Nada nothing! I did not know before hand of all the stories. Plane was stable and did not vibrate in excess.:D Had prop on and no tail. I think if you need to do some checks and tie it down and chock it and are careful and not rev it or chop the throttle you'll be fine. But as a safety reminder your mileage may very and it's up to the individual to take that chance just like getting in the plane or car or whatever it is, it's your bacon!:eek:
Scott
8A

I know a guy that once jumped without a parachute and lived therefore you'll be OK, jump!
But if you die it isn't my fault .
For the hundredth time anecdotal evidence is worthless. Easy to spout advice when there is no skin in the game.
Ask your inspector to run it with the caveat that he pays for any damage that may occur.
 
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Your engine should remain pickled until you are very near first flight. Nothing is gained by running it early.
 
Thanks for all the replies. My local airfield (EGTR) will only give me hangar space for a couple of days to do final assembly, hence my desire to do as much as possible at home before the final assembly. Its not a financial issue, just the management seemed totally uninterested in helping as they are over capacity with the closure of a nearby airfield and the overspill of evicted planes needing somewhere else to live. :(

Perhaps i should look for an alternative airfield but I know the extended driving distance will hinder the final progress.

I wont risk 4 years hard work so will wait for engine running until the wings are on. Its a new factory built lycoming.
 
Not exactly like a robust RV gear but still ....

http://m.youtube.com/watch?v=EHt6nYTdmRQ

This video does not apply to RV's. If you look closely, the gear starts to retract as soon as the engine starts. It has everything to do with bad procedures. Somewhere there is an article about what went wrong.

While I don't know if running the engine without the wings installed or not, I would run it only after the wings and ALL controls are installed and connected. Besides, there is no problem waiting until just before your first flight.

FYI - it took me exactly one month from the day I moved my plane to the airport and my first flight. I could only work on Saturdays and Sundays.
 
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Van's has recommended against it because of actual instances of damage to airplanes from doing,.....The problem seems to be related to the rotational inertia damping provided by the wings.

Scott,

Can you tell us which specific component(s) may be or have been damaged?

Specific information does wonders.
 
Scott,

Can you tell us which specific component(s) may be or have been damaged?

Specific information does wonders.

It has been a long time now, so the only things I can specifically remember is elevators and possibly rudder but there could have been damage to stabilizers and fuselage also.... just can't remember.
I imagine it is because of the undamped roll induced at start up and shut down, inducing high torsional loads in the elevators because of the counterweights (rolling shake working against the inertia of the elevator counter weights.
There is no data that I know of indicating type of engines and propellers (high compression, light vs heavy prop. etc.), which could all have some influance, which may be why some people have gotten away with it and others have not.

Hence the conservative stance.....
 
It has been a long time now, so the only things I can specifically remember is elevators and possibly rudder but there could have been damage to stabilizers and fuselage also.... just can't remember.

That makes sense. The one I saw probably didn't have the tail mounted.
 
Just curious

Not trying to be the hair in the frosting here, but can somebody explain why it would be necessary to run the engine without the wings. What is it that cannot be accomplished later when the wings are on and the plane is near ready for flight? There may be a reason but I've been trying to thing of one.

I'm also curious if the the front top skin is permanently installed on the plane. If it is just clecoed, more potential for problems.

Van's doesn't recommend it. The other aspect that hasn't been mentioned is insurance. Hmmmm........ Why tempt fate?

If it is predictable, it is preventable!!!
 
My local airfield (EGTR) will only give me hangar space for a couple of days to do final assembly
The "installation test run" of the engine takes about 5 mins cowling off, 10 mins cowling on. Are your local airfield being that restrictive :eek:

Your problem will be that when you have test run the engine (wings on :D) and the inspector signed everything, it will be ~4 weeks until you get the Permit to Test anyway...
 
Thanks for all the replies. My local airfield (EGTR) will only give me hangar space for a couple of days to do final assembly, hence my desire to do as much as possible at home before the final assembly. Its not a financial issue, just the management seemed totally uninterested in helping as they are over capacity with the closure of a nearby airfield and the overspill of evicted planes needing somewhere else to live. :(

Perhaps i should look for an alternative airfield but I know the extended driving distance will hinder the final progress.

I wont risk 4 years hard work so will wait for engine running until the wings are on. Its a new factory built lycoming.
You are going to need more than 4 days. If no hangar space you going to park a new airplane outside?
Gonna have to find another airport and make the drive. Maybe find some local RV builders too lend a hand with completion.
 
The YouTube video of the fuselage dancing without the wings was I believe a Lancsair 360. It was so scary looking. Maybe somebody can find that video. doNOT start the plane without the wings!
 
Oooooo,

This is like Primer Wars - Most Excellent !


Here is why I ran mine and what we did.

My workshop is in my garden and is fully equipped - the airfield is 30 miles away and is just that - a hangar and a strip.

My motor was a brand new, test cell run, inhibited ECI IO-360 assembled by Mattituck.

Apart from assembly, we thought the aeroplane was ready to fly.

I wanted to ensure that the basics were OK before we went to the strip and were detached from tools, plans, facilities - oh, and a good heater !

The aeroplane was weighted down, had no empennage on, was securely tied to a 6" gatepost and chocked.

Firstly, the inhibitor oil was flushed by putting 4 quarts of fresh low weight oil in and spinning the prop over by hand without plugs in. The oil was drained and fresh put in. That raised a sweat !

A gallon can of fuel was plumbed in and secured to the left hand wing root.

My Bro and I discussed what we were trying to achieve, we had set signals and 2 fire extinguishers on hand with a third person on the other side for safety.

The engine started on the third blade.

It ran at around 800rpm for a minute or so - leak checks OK, Oil pressure OK, electrics checked, systems powered up and checked. I ran it up to to 1200 and checked the mags - 1 side was dead.

Hmm......

Stop, think, 3rd man now underneath checking for leaks, things dropped off etc.

Started again - same.

No operations over 1200 rpm.

OK - back in the shop, pleased with everything apart from mag dead.

We changed our ignition from LASAR to P Mags during the progression of the build and had installed P Mags on both sides.

In the warmth and comfort of the workshop, we could now fault find and went carefully through the install, retimed the mags and was about to take it out again when it struck me.

Why was the left mag set back from the case so much ?

Yep - impulse spacer was still in :rolleyes::eek:

30 minutes later we were outside, part deux.

Started, ran, pressures checked, mags checked - STOP.

That was it - we function checked and systems checked everything in the comfort and safety of our workshop rather than on a cold and remote hangar.

It worked for us, safety was paramount, a plan was in place and a structure to what we wanted to achieve. Yes, there was video but that was by an unattached independent.

I reported this years ago when we did it and got flamed and applauded so you will never win.

Choose your own path and BE CAREFUL !!
 
The YouTube video of the fuselage dancing without the wings was I believe a Lancsair 360. It was so scary looking. Maybe somebody can find that video. doNOT start the plane without the wings!

That LancAir's gear started to retract when the engiwwas started. IIRC, it was wired incorrectly and had nothing to do with the lack of wings.

I'm not saying running an RV without its wings is a good or bad thing, just that you can't use that LancAir video to prove a point about an RV.
 
Good points

My point in posting the Video wasn't trying say Lancair equals RV. I was pointing out that be prepared and as best as possible cover all the bases .... Good or bad!!!
 
My point in posting the Video wasn't trying say Lancair equals RV. I was pointing out that be prepared and as best as possible cover all the bases .... Good or bad!!!

I understand but my point is that RV's don't have to worry about the gear retracting at engine startup. (Well, most RV's don't have to worry.) What we learned from that video and subsequent posts by the builder is that the gear would have retracted even with the wings on.
 
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