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Run engine w/o wings

rileyspoon

Active Member
Seems like I saw a thread where it was being discussed if it were advisable to run the 912iS without the wings attached? Can't seem to find it now though.
Anyone remember such a discussion? I've seen a video of someone testing their engine on an RV-12 build and the wings were not attached.

Thoughts?
 
I read early on that the RV12 has a safety switch to prevent the starting of the engine unless both of the wings are installed onto the fuselage.
 
Yeah, I remember reading somewhere that they started installing those switches after somebody forgot to put their wings on and went off the end of the runway at over 100 mph.
I read it on the internet so it must be true...
 
Engine Start

I read early on that the RV12 has a safety switch to prevent the starting of the engine unless both of the wings are installed onto the fuselage.

Not quite correct. The wings pins must be in place. They can be in place without the wings being installed.
 
Mine has the override button next the the starter which I hold down to start without the wings on.
Just did a wingless start, warm up, and run up to check things after changing the coolant hoses, and condition inspection. Also did a carb sync.
Didn’t taxi around without the wings and climbing in and without the wing to step on makes me pay closer attention so as not to miss the step.
 
Yes I knew about the wing pin disconnect and override but I thought I had seen a post that express some concern about torque load on the fuselage when the wings were not attached?
 
I did my first few runs without the wings. No issues, but I got some funny looks as I taxied around the airport.😜
 
What you are speaking of is the twisting force (torsion) put on the airframe when the engine is starting. Without the wings on you put a higher twisting force (torsion) on the airframe without the wings to counter act the mass of the twisting airframe.
 
Dave,

Having the wings on would increase the moment of inertia, but the torque on the engine mount is the same with and without wings. The wings just make it less obvious when looking out the windo.

Rich
 
Dave,

Having the wings on would increase the moment of inertia, but the torque on the engine mount is the same with and without wings. The wings just make it less obvious when looking out the windo.

Rich

I said nothing about the torque on the engine mount. I said airframe.


From Scott" The reason it is not recommended on the other RV models has nothing to do with fuselage strength (and it is not because of a fear of it rolling over). It is because of the inertial damping in roll that the wings provide.The majority of the shake induced by a Lyc. is in roll. Without wings installed, there is much less mass to limit the shake.
There are documented cases of RV's having elevators and rudder damaged because of an engine start/shut down without wings installed.
Can it be a problem with an RV-12? Probably not, but I cant' say for sure because we choose not to take the chance."
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Can you point me to a discussion of those documented cases? I find it difficult to believe the tail feathers are that fragile, but I have an open mind to the data.
 
Can you point me to a discussion of those documented cases? I find it difficult to believe the tail feathers are that fragile, but I have an open mind to the data.

Look at the link in post #11 below. Vans (the kit manufacturer) says it’s not recommended...So why would we think it’s ok?!?

:eek:
 
Like I said, I’d be interested in reading the documents on the documented cases to better understand exactly what happened. I have an open mind, I just like it when statements have some objective evidence to evaluate for myself.
 
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