What happened to my Tiger ..

[PJ Rowland]

So many of you know that I was planning on flying my Newly finished tiger model for the US NATS however did not see me fly it.

I have been very candid and forthcoming with my reasons for not flying my main model in Open - I certainly did'nt set out to prove anything with flying the Gieseke Nobler, it just happened - it was all that I had to be able to fly it.

I had 12 days of full time practice in Australia prior to leaving for the USA and had the model in really nice trim. We arrived in Muncie the Monday before everyone else, so I had 4 days of full time practice with noone around. I also spent those 4 days filled with frustration - I could not for the love of God get the model to Sit right, to track correctly, or even to Run correctly.

The Running correctly I sorted out with Fuel, and a vibration issue. However the trimming issue remained a mystery. Initially I thought It might have been something to do with the Air Density, the altitude, or the site, but no matter WHAT I did, I could not get it to fly even CLOSE to what I had it in Melbourne.

I asked many of my peers during official practice, if they had any solutions, I had exhausted everything. The main issue was a lack of penetration in any outside manouver. Esp at the top of the Vertical 8. It was flying wings level in Level Flight, but wingtip Up Inverted.. A real Head Scratcher.
Imagine flying a model 1 day perfectly, then taking it out 2 days later and have it nothing close to how it was.. this was my Dilemma.

I even took some epoxy and glued my outboard trim tab to the Flap to increase my outboard span area, to try to tweak the wings to sit level, but could not get it to work..

I will plead ignorance when I say that I did'nt think for a moment that I might have a Misalignment, or even heaven forbid - A warp.  It wasnt until Sparky came over and said - Let me have a look at it, it probably has a warp.. I cam remember saying " Nope its dead straight that much you can be sure of "

Well wouldnt you know it - he saw it, and to be honest I didnt look for it, but it was fairly obvious.

We tried to get it out at the hotel, but failed after 2 hours over steam and heat..- Sparky offered to get it out ( which im sure he could have ) however after Classic ( day prior to open ) I left his number in my back pocket and proceeded to take a swim.. I took it as a sign that I should simply forget about it, cut my losses and move on.


I have zero explanation for the cause of this.. The most plausable explanation I've heard is the change in pressure associated with Transatlantic flight where the cabin below isnt pressurized - combined with the heat in Muncie - combined with possible differences in finish coat density caused it to move.
It also did happen on the inboard wing and seems locaized to roughly 10 inches into the wing.. so perhaps the dual leadouts provided some area for moisture to get in.. I really do not know.

I brought 3 planes over and neither of the other 2 warped. Not even the flaps went on the tiger.

Was it there prior to leaving ? No I didnt have any trim issues in the 10 days prior - but once I arrived it was a difference plane..

Was it there after the finish was applied? Well you can see by the photos' I carbon Veiled the wing twice, and as you can see in the photo's its still straight. This is where you would imagine a warp would start in the application of Dope to Airframe.

I have no further explanation, no advice, I will take this as a random event - Nats badluck so to speak..

See photo's to see how bad it was - The bottom photo is the day I landed back home.

[Peter Nevai]

I distinctly remember your shipping box. You may want to double check how the model rests in the box. As I recall the box held 2 planes. When loaded in the box, is the supporting packing placing any pressure on the wings relative to the fuse? It is quite possible that the shipping box or it's padding applied a twisting pressure on the airframe. Then with the change in temp and atmospheric pressure with possible condensation, coupled with the plane having a twisting force applied for the duration of the flights (over 14 hours) caused the warps to set in. thats where I would start.

[Michael Schmitt]

As a note pj, As a Aircraft Mechanic (technical crew crew chief) for American Airlines.The cargo compartments are also pressurized. But even a pressurized cabin is still about 8000 above sea level.

[Tim Wescott]

Surely you mean the top photo is the day you arrived back home?  It took me a while to see the twist, but once I did -- wow!

Perhaps the inner wing tip is sensitive to gyroscopic forces, and due to the apparent reverse rotation of the earth as seen in the Northern hemisphere the wing twisted itself to compensate?

No, wait -- that wouldn't account for the twist persisting when you got home...

It's a good thing you had extras!

[Peter Nevai]

As a note pj, As a Aircraft Mechanic (technical crew crew chief) for American Airlines.The cargo compartments are also pressurized. But even a pressurized cabin is still about 8000 above sea level.

True mamy airlines pressurize the cargo sections, especially if pets are transported, but the temp is not as well controlled, and coupled wirh luggage sitting out on the tarmac in the sun, if the shipping box interior is not square to the model or other luggage is distorting the shipping box for hours I can see the mechanism for the warps.

[PJ Rowland]

Fair enough.. I dont have any reasonable explanation.

As for my shipping box.. it was CNC foam milled to the exact dimensions of the model, there was ZERO movement so I know thats not where the cause lay.

Overall it was warped up 1/2 - 3/4 " It will be scrapped, My next one will be foam wing.

[Howard Rush]

I wish I had known about it.  Or if you did tell me about it, I wish I had processed the information (my mind did not work well at Muncie).  I had serious dewarping technology with me, and we could have straightened it out.  Leaving an airplane in a hot car with any part of the wing touching anything else can cause a warp.   

[Wynn Robins]

Fair enough.. I dont have any reasonable explanation.



Overall it was warped up 1/2 - 3/4 " It will be scrapped, My next one will be foam wing.

chuck it is  box and send it over the ditch.......I can de-warp it - but you wont get it back 

[PJ Rowland]

Its ok - I had a few people say they could get it out, - the issue really in the end was time. I only discovered the problem the day prior to apperance judging, so I had to make a call after we tried to get it out ( incidently we applied so much force for those 2 hours we crushed some of the tip and rippeled some of the top coat of paint where it we were flexing it) Combined that with the fact I had vibration issues caused by a crack near the wing - which was caused by the crash back Home 4 days prior to leaving which was caused by a failed Bellcrank ( My fault ) I jsut had too many things I was concerned about and time just wasnt' with me.

I decided to cut my losses and fly what I knew would perform well. Even if I had of flown the Tiger I might only have place 3 -4 places higher so it really wasnt any problem.


Thanks for that Howard : Next time I will make sure I bring over something else warped for you to use your dewarping technology. On a side note : What would you have tried?


Wynn - You dont want that piece of rubbish - I need all the comp spec controls out of it. I will post photo's of the deconstruction of the model..... Win some you loose some.

[Peter Nevai]

Fair enough.. I dont have any reasonable explanation.

As for my shipping box.. it was CNC foam milled to the exact dimensions of the model, there was ZERO movement so I know thats not where the cause lay.

Overall it was warped up 1/2 - 3/4 " It will be scrapped, My next one will be foam wing.

Zero movement is what could have caused it. If the foam cutouts and filler material put uneven pressure on the airframe, the very pressure that kept the model ftom moving could easily press in the warp. I would not consier that the cause if there was free space around the model. In that case there is nothing to supply a constant pressure against the wings. Consider that there could have been hundreds of pounds of luggage stacked on your box for many hours at a time. If the cushioning material is too tight and not yeilding enough it's like putting the model into a mold, which will force the model to conform to it's shape.

You said it yourself, the model was fine before going into the box but was not immediately after removal.

[Howard Rush]

What would you have tried?

A teakettle for starters.  I hesitate to respond, because this always evokes a bunch of folk remedies.

[PJ Rowland]

Hindsight is a wonderful thing, Sparky suggested a tea Kettle, all I could find in a hurry was a roasting pot with boiled water.

The box wasnt the problem.. Its fairly strong foam, you can stand on it, and will resist crushing. I have no doubt the issue lay elsewhere. We took 3 model over.. there were 2 models in one of my boxes. The other 2 survived undamaged. Im not discounting the possiblity that during the dope phase there was an uneven amount applied to top vs bottom, or even out toward the tip, this could have yeiled a predisposition to a warp. Muncie heat and humidity could have been contributing factors.

Overall Im not really that concerned about it anymore, Im not even dissapointed ( I mean I am .. but Im over it now ) Sometimes things happen that are out of our control.  Whats the expression : The best laid schemes of mice and men..


I wanted to let everyone know who didnt get to see it what the problems were.. perhaps I should have pushed harder to try and remidy it.

[Douglas Ames]

Well...Our toilets do swirl in the opposite direction of yours. 

[Tim Wescott]

I wanted to let everyone know who didnt get to see it what the problems were.. perhaps I should have pushed harder to try and remidy it.

I haven't been to a lot of contests, but I have been involved in a lot of product design efforts that culminated in last-minute pushes to get stuff out the door.

There's always a tendency to try to keep plan A alive, even when it's clear that the patient is dead and has already started to rot.  Some times the best thing you can do, even at the last minute, is to dump your mistakes into a hole and cover them with six feet of dirt.

I wasn't there, but looking at that wing I can't imagine being able to get it straight and true and having it stay that way through a day of flying in hot humid conditions.

[M Spencer]

If you put a couple of 4 x 4s on the lawn at the spars , lay it on upside down ,
chuck a 6 x 1 on that wing, and put 3 bricks on it, with one under it to stop it twisting to far 

set up / blocked up right , and with the dew overnight , getting it to go 3/4 opposite over a few days
when you hung it on the wall for a week it would probly still be twisted opposite. repeat proportionately.

IF there was some BUTRATE in there somewhere , theres a remote possibility it might have had something to do with it, and when they left the box by the air - co outlet when they lost it at the airport .

[PJ Rowland]

Thanks for the kind words.

This is really the first model I've had that was pulled from service due to a Warp. Sure we have all had problems one way or another, but this was quite strange - I have already started on my new one, and I still have my 09 - 2010 model which remains unflown.

[Matt Colan]

Thanks for the kind words.

This is really the first model I've had that was pulled from service due to a Warp. Sure we have all had problems one way or another, but this was quite strange - I have already started on my new one, and I still have my 09 - 2010 model which remains unflown.

Also the bellcrank pulled out in an extremely weird way according to your dad also!

[PJ Rowland]

Yes I mentioned this elswhere but the Bellcrank pulled out 4 days prior to leaving.

I secured teh bellcrank pin between 2 maple barers but I have not ever capped the top of the bellcrank pin. Over the corse of the flights, it wriggled its way vertical and pulled out of the hole, jammed full down and went in. Lucky it was soaking wet and muddy, broken prop and some damage to the front ( which later caused my engine run issues, the whole fuse was flexing.

We fixed it back in, re paininted the entire top block, but it was never as good as the first time it was finihsed.

Thems' the breaks.. it raelly just wasnt the contest for this plane.

So not a weird way, more like a stupid bonehead way. Brett Buck told me at the Nats " Everyone now secures the top to something.. " Wish I knew.. I will in the future however.

Doesnt matter, new model is underway

[john e. holliday]

Not only do I have lthe bellcrank pivot going all the way thru both surfaces with ply pads butted to fuse sides.  It is long enough that I grind some slits in it for the epoxy to grip onto.  If you look close you will see the pad on top  of the wing.  An identical pad on the bottom side also.   

[M Spencer]

whipping a rebate at the ends to take a 'C' clip , & a bit of epoxy  belt & braces .