Composite-ARF Impact question

[Bill Southwell]

    Sounds like a twisted stab to me. If it has gotten a bit hot in 
transit with any torsion it would twist. I have heard stories of fellows 
leaving the airplane in the van on a hot day and it had something 
pushing on the fuse.....it cools over night and walaaa  instant flying 
bannana. It could also be a bad mold but hey, I am sure, as some are to 
so  eager to point out, that our offshore suppliers are incapable of 
having a less than perfect quality product. Now if the kit had been 
produced in the states the warp would have been the first and loudest 
possibility....Gee, I just slipped my nomex suit on so flame away. :>)  
My guess is that heat and pressure induced  a ahh ..modification to the 
fuse and is the source of the off set fin. Besides I doubt the 
manufacture would miss a chance for a " great new feature" to not have 
used it in the ad copy if it were intentional..... 

Bill "call me charcoal now" Southwell
Iuka,MS




Adam Quennoz wrote:

> I've done some more investigating.  I traced the outline of the 
> airfoil on top of the v. stab on a piece of paper.  It is 
> symmetrical.   Now the kicker....  I drew a centerline on the top of 
> the stab.  Then stood behind the plane and sighted down the line I 
> made.  It pointed WAY off to the left.  So there is definately 
> something going on with the vertical stab.  I still can't figure out 
> if it's a design feature or a mistake.  I guess the question to ask is 
> if anyone out there flying this plane notice any difficulty in 
> trimming or anything out of the ordinary while trimming?  I'm also 
> curious what Jason Shulman has to say about this.  Does he know it is 
> there?
>
> Regards,
> Adam Q
>
> Bill Glaze wrote:
>
>>
>> As I recall, this thread started because of one flyer noticing the 
>> asymmetrical airfoil on his new fuselage. While certainly not 
>> original in aviation, I must admit that I've not seen this before in 
>> the modeling world.  Or, probably, it's just that I've not noticed it 
>> before.  I sure hope he keeps us updated as to how it works in the 
>> real world of modeling.
>>
>> Bill Glaze
>>
>> Bob Richards wrote:
>>
>>> Bill,
>>>  
>>> I don't think it is uncommon for full-scale planes to have offset or 
>>> asymmetrical fins. However, they are designed with the right amount 
>>> *for cruise*. Any other speed/power setting will change things. 
>>> Since they are after the most efficiency in cruise conditions 
>>> (better range), they will probably want the least amount of offset 
>>> thrust as possible, and will trim the rudder/fin accordingly. If 
>>> they expect the fin to be providing a constant yaw force, it would 
>>> make sense to give it an asymmetrical airfoil for the most 
>>> efficiency. Let the pilots deal with the other situations.
>>>  
>>> I personally think the right-thrust is the correct way to go. I 
>>> can't argue with what others have said about throttle mix working 
>>> for them, but I don't see how it would work. I think you will have 
>>> less slipstream effect happening at full throttle in level flight 
>>> than you would at full throttle in a climb. As the prop unloads with 
>>> increasing airspeed, the slipstream effect should decrease.
>>>  
>>> Of course, I remember the very detailed trim instructions that came 
>>> with my Great Planes Cap21. Something like: "Pull the nose up until 
>>> pefectly vertical. If the plane yaws off to the left, add weight to 
>>> the right wingtip". There was no mention ANYWHERE about engine 
>>> thrust. Tossed that in the trash. :-)
>>>  
>>> Bob R.
>>>
>>> */Bill Glaze <billglaze at triad.rr.com>/* wrote:
>>>
>>>     Adam:
>>>     This may be a little bit off the mark, but just a little bit. 
>>> During
>>>     WW2, the Italian firm Fiat produced a very good series of
>>>     fighters with
>>>     exactly the characteristics you mention, that is, an asymmetrical
>>>     fin/rudder airfoil. Seemed to work well for them; other nations
>>>     handled
>>>     the problem differently.
>>>     Bill Glaze
>>>
>>>
>>>
>>> Bob Richards
>>> bob at toprudder.com
>>> http://www.toprudder.com 
>>
>>
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