Anybody give your engine a test run in the driveway without the wings installed? Sure would like to do this prior to moving everything to the airport in a few months. Obviously taking all the fuel/fire precautions and ensuring kids,pets and neighbors are notified I can't think of a reason why using a properly grounded gas can and chocked plane would be a problem. Thoughts?
Van's Air Force
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Starting Engine In Drive-Way
- Thread starter RV8R999
- Start date
John Clark
Well Known Member
Start it when the airplane is ready to be flown.
Along with the very real safety concerns, if it is a new engine, you really don't want to run it and then let it sit for "a few months" unless you pickle it for storage. Hangars are really good at making condensation.
John Clark ATP, CFI
FAA FAAST Team Member
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
Along with the very real safety concerns, if it is a new engine, you really don't want to run it and then let it sit for "a few months" unless you pickle it for storage. Hangars are really good at making condensation.
John Clark ATP, CFI
FAA FAAST Team Member
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
WOW!!! I won't be doing that I can tell you. Those gear legs folded like noodles. Something else besides not having wings must have been going on with that plane. Im not familiar with LANCAIR gear design but the oscillation after he jumped the chocks was probably exacerbated by the low empty weight leaving the gear with much less preload thereby changing the resonant frequency of the spring/mass/damper system...I'm only guessing. Can you imaging how bad that guy must of felt after that!
Ok.I'll wait. That was enough for me.
Thanks!!!
Ok.I'll wait. That was enough for me.
Thanks!!!
Kyle Boatright
Well Known Member
I think the airplane only jumped the left chock. The right one did a great job folding back the gear on that side. I'm guesing his downlocks weren't properly installed.
That had to be a bad day...
jcaplins
Well Known Member
That's a pretty damning video, but I don't think it proves the point.
I'm not trying to be contradictory.... I agree with all the reasons for having the wings on before firing up the engine.
I have seen that video used many times to support the argument. I also believe that the problem in the video was the gear being retracted (it's not a fixed gear), which may or may not have had anything to do with the wings.
just saying is all.
I'm not trying to be contradictory.... I agree with all the reasons for having the wings on before firing up the engine.
I have seen that video used many times to support the argument. I also believe that the problem in the video was the gear being retracted (it's not a fixed gear), which may or may not have had anything to do with the wings.
just saying is all.
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N941WR
Legacy Member
IIRC, that Lancair was an RG and the Gear started to retract, which is why he had a problem.
I know of one RV-8 that was run w/o the wings on and with no problem. However, if it were me, I would want the wings and all the control surfaces installed so I had some control, if it started to move.
I pushed my homebuilt, not an RV, out of the shop and chained it to a tree for the first start, no problems. It was a mid-time engine and I don't live in town. Be sure your pets and children are away and nothing is around that can get sucked up by the prop. If you're not going to be flying soon you will need to pickle your engine. You can spray oil in the carb until the engine dies and that helps, but it still needs more for long term storage.
FWIW, I've also witnessed an RV6 started without wings, no problem at all, shake or otherwise. Of course the owner was smart enough to tie it to a truck......
That said, I don't recommend it for the reason John mentioned; you don't want to unpickle until time to start flying.
That said, I don't recommend it for the reason John mentioned; you don't want to unpickle until time to start flying.
jcbarker
Well Known Member
Proof of an -8 started without wings
No big deal. Like Dan said, no shake. Probably didn't need the side tie downs but it was easy to do. Good chalks under the wheels and you'll notice we tied the tail to a tractor! As you can see, the airplane was done. So it didn't have a chance to sit around long before it was flying.
No big deal. Like Dan said, no shake. Probably didn't need the side tie downs but it was easy to do. Good chalks under the wheels and you'll notice we tied the tail to a tractor! As you can see, the airplane was done. So it didn't have a chance to sit around long before it was flying.
Junglepilot
Well Known Member
No problem if you take precautions
When I was overseas with MAF, we had a Cessna 180 that had it's wings off for extended maintenance that we did not want to have corrosion start in the engine. So we ran it every week.
We took a spare/used oil external oil sump from another 180 (which held about two gallons if I remember) and mounted it securely to the right wing root, ran the proper hose and with fittings into the header.
We then pulled it out to an adjacent field next to our main hangar, tied the tail wheel to two in ground heavy duty tie-downs, set the yoke to full up elevator, set brakes and chocked the wheels with oversized, metal chocks.
Next had a man stand buy with a large halon extinguisher.
We ran it this way each week for about 5 months until it was back in service. The engine went to TBO and no surprises.
Just use common sense. That video with the Lancair is indeed sad but that one leg look tweaked when the video started. I believe there's more to that story than the 10 seconds of shakey footage show.
When I was overseas with MAF, we had a Cessna 180 that had it's wings off for extended maintenance that we did not want to have corrosion start in the engine. So we ran it every week.
We took a spare/used oil external oil sump from another 180 (which held about two gallons if I remember) and mounted it securely to the right wing root, ran the proper hose and with fittings into the header.
We then pulled it out to an adjacent field next to our main hangar, tied the tail wheel to two in ground heavy duty tie-downs, set the yoke to full up elevator, set brakes and chocked the wheels with oversized, metal chocks.
Next had a man stand buy with a large halon extinguisher.
We ran it this way each week for about 5 months until it was back in service. The engine went to TBO and no surprises.
Just use common sense. That video with the Lancair is indeed sad but that one leg look tweaked when the video started. I believe there's more to that story than the 10 seconds of shakey footage show.
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az_gila
Well Known Member
The other problem...
...may be blowing your neighbors roses away....
One S. Cal builder showed how this could be done... and another started his engine in a small enclosed back yard, and didn't warn his wife, who was p***d off that all of the back yard dirt blew into her kitchen....
Those large propellers do create a lot of "wind"....
...may be blowing your neighbors roses away....
One S. Cal builder showed how this could be done... and another started his engine in a small enclosed back yard, and didn't warn his wife, who was p***d off that all of the back yard dirt blew into her kitchen....
Those large propellers do create a lot of "wind"....
Andy Hill
Well Known Member
Whilst building the RV-3 fuselage, it suddenly struck me there was a discontinuity in major longerons in the lower fuselage between the main and rear wing spars...
It made me go back to the plans and check I had not omitted something... and then realised, no I had not, the "load" path is provided by the wing structure itself.
If you do choose to run the engine without the wings bolted on, think through how the "box" rigidity of the fuselage (in twist) is compromised by no wing box, and also the straight line path from engne to tail (i.e. tying the tailwheel down does not really help since there is a structure "gap" between the wing spars). Trying to quantify these elements is nigh on impossible - the only people qualifed to answer are Vans, and we know their opinion on the matter
Andy
It made me go back to the plans and check I had not omitted something... and then realised, no I had not, the "load" path is provided by the wing structure itself.
If you do choose to run the engine without the wings bolted on, think through how the "box" rigidity of the fuselage (in twist) is compromised by no wing box, and also the straight line path from engne to tail (i.e. tying the tailwheel down does not really help since there is a structure "gap" between the wing spars). Trying to quantify these elements is nigh on impossible - the only people qualifed to answer are Vans, and we know their opinion on the matter
Andy
An RV10 no wing engine startup. No problem.
http://www.youtube.com/watch?v=0LgG6J8UyPE&NR=1
That being said, I will still wait for my wing attachment before running mine the 1st time. A couple years ago I wanted to start it sitting on an modified engine stand w/o prop. But, back then I was considerably more ignorant than now..... Now, I'm only slightly ignorant... big improvement thanks to VAF...
http://www.youtube.com/watch?v=0LgG6J8UyPE&NR=1
That being said, I will still wait for my wing attachment before running mine the 1st time. A couple years ago I wanted to start it sitting on an modified engine stand w/o prop. But, back then I was considerably more ignorant than now..... Now, I'm only slightly ignorant... big improvement thanks to VAF...
Whilst building the RV-3 fuselage, it suddenly struck me there was a discontinuity in major longerons in the lower fuselage between the main and rear wing spars...
It made me go back to the plans and check I had not omitted something... and then realised, no I had not, the "load" path is provided by the wing structure itself.
If you do choose to run the engine without the wings bolted on, think through how the "box" rigidity of the fuselage (in twist) is compromised by no wing box, and also the straight line path from engne to tail (i.e. tying the tailwheel down does not really help since there is a structure "gap" between the wing spars). Trying to quantify these elements is nigh on impossible - the only people qualifed to answer are Vans, and we know their opinion on the matter
Andy
It really is amazing what we are learning by actually BUILDING our aircraft structures, isn't it Andy? The load paths are much more understandable when you put them togteher....
Paul
Bill Wightman
Well Known Member
RV8 Driveway Run
Ran up my RV8 / 180 CS sans wings without issue. *However* there could have been problems stemming from a couple areas.
Video Link:
http://www.youtube.com/watch?v=JHQfhOiyKQM
Tail shake: Mine didn't seem to have a real issue with tail shake, but I couldn't have known that at the time. Its since been brought to my attention that the wings do provide a good amount of mass damping to the fuselage and will help to reduce tail shake during startup/shutdown.
The wings also contribute a good bit of weight to the tail so the plane is considerably lighter on the tail without wings. My solution to that was to tie the tailwheel spring to the rear axle of a Chevy 1500. But that still wouldn't prevent it lifting up a couple feet with enough thrust up front.
Second: the torque impulse reacted by the landing gear looked worse on video than it felt in the cockpit. In the video, you can see both gear legs flexing a fair bit as the engine stumbled to life out of a slightly flooded state. To me, it didn't feel or look unstable or apt to tip over but the torque reaction, being entirely reacted by the gear & fuselage inertia, was somewhat more than I was accustomed to.
Y'all can draw your own conclusions. I for one didn't have any problems. But, the wings definitely do contribute additional mass stability to the airplane so if you feel like you need that, then by all means put them on. I personally have no fear of a tip-over so long as the airplane is secured to something that won't move, as was evident in the video. Structurally, I see no reason the wings need to be on for a simple ground run, other than their mass damping effect. They definitely do not add stiffness to the fuselage. The spar carry-through section is stiff transversely, but that stiffness isn't critical for this kind of operation.
Ran up my RV8 / 180 CS sans wings without issue. *However* there could have been problems stemming from a couple areas.
Video Link:
http://www.youtube.com/watch?v=JHQfhOiyKQM
Tail shake: Mine didn't seem to have a real issue with tail shake, but I couldn't have known that at the time. Its since been brought to my attention that the wings do provide a good amount of mass damping to the fuselage and will help to reduce tail shake during startup/shutdown.
The wings also contribute a good bit of weight to the tail so the plane is considerably lighter on the tail without wings. My solution to that was to tie the tailwheel spring to the rear axle of a Chevy 1500. But that still wouldn't prevent it lifting up a couple feet with enough thrust up front.
Second: the torque impulse reacted by the landing gear looked worse on video than it felt in the cockpit. In the video, you can see both gear legs flexing a fair bit as the engine stumbled to life out of a slightly flooded state. To me, it didn't feel or look unstable or apt to tip over but the torque reaction, being entirely reacted by the gear & fuselage inertia, was somewhat more than I was accustomed to.
Y'all can draw your own conclusions. I for one didn't have any problems. But, the wings definitely do contribute additional mass stability to the airplane so if you feel like you need that, then by all means put them on. I personally have no fear of a tip-over so long as the airplane is secured to something that won't move, as was evident in the video. Structurally, I see no reason the wings need to be on for a simple ground run, other than their mass damping effect. They definitely do not add stiffness to the fuselage. The spar carry-through section is stiff transversely, but that stiffness isn't critical for this kind of operation.
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kentb
Well Known Member
I didn't start mine until the day before the first test flight.
I didn't avoid the early start up because of structural reasons, although it looks like that should be considered.
The reasoning used for the delay about starting the engine are as follows:
I try to fly my plane once a week. If for some reason I can fly for a month, I start getting concerned about not doing the best for my engine. If you keep the oil moving on a regular basis your engine will last longer.
My engine was shipped to me with preservative oil in it and was setting in my hangar, on a pallet and then on the plane for more then one year. Before starting the engine the oil needs to be drained and fresh oil put in.
After the first start the engine is in the non preserved state and the clock starts ticking. Now the pressure is on to get it in the air and I don't like being under pressure to complete the build. At the end stage of the project you need to take your time and make sure everything is right.
Kent
I didn't avoid the early start up because of structural reasons, although it looks like that should be considered.
The reasoning used for the delay about starting the engine are as follows:
I try to fly my plane once a week. If for some reason I can fly for a month, I start getting concerned about not doing the best for my engine. If you keep the oil moving on a regular basis your engine will last longer.
My engine was shipped to me with preservative oil in it and was setting in my hangar, on a pallet and then on the plane for more then one year. Before starting the engine the oil needs to be drained and fresh oil put in.
After the first start the engine is in the non preserved state and the clock starts ticking. Now the pressure is on to get it in the air and I don't like being under pressure to complete the build. At the end stage of the project you need to take your time and make sure everything is right.
Kent
rodrv6
Well Known Member
Heck, the first time I ran my RV6 it was still in the workshop! Of course, I did not put the prop on for the first runs, and did not run the engine beyond a fast idle. (That's one advantage of a Subaru--makes it very easy to check for leaks and such without worrying about getting caught by the prop). I did do some outdoor runs in the driveway with the prop installed, but no worries about shutdown "shake".
