[NSRCA-discussion] Wheel Pants Yes or No

[Rcmaster199 at aol.com]

On full size planes they add considerable range to a tankful of gas. There's 
a small reduction in drag with them on models...BUT...SO WHAT?? We strive to 
achieve a constant speed model so a bit more drag is a good thing when one 
considers the powerplants we have available to us. 
 
To me, wheels without pants on a model are similar to car's wheels without 
hubcaps. The look to me is Not aesthetically pleasing. On occasion I have had to 
resort to tossing the pants off my models also. Sometimes practicality wins. 
For example the baby Oxalys comes with pants that are just too heavy and large 
for the size of the model. Didn't feel like designing an appropriate set for 
mine and making a mold for a new set, SOOOO, the baby Oxalys will go without 
pants. In a matter of speaking....it will stay in diapers (VBG)
 
MattK
 
 
 
In a message dated 5/5/2007 9:29:41 AM Eastern Standard Time, 
gene.maurice at sgmservice.com writes:

Empirical results. A 10lb 14 oz Eclipse flown for a few months with the wheel 
pants (3 oz.) on. I took them off for a contest to be flown off of grass. NO 
NOTICABLE TRIM DIFFERENCE.  
Gene Maurice 
 
  
____________________________________

From: nsrca-discussion-bounces at lists.nsrca.org 
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Fred Huber
Sent: Friday, May 04, 2007 11:17 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] Wheel Pants Yes or No
 
Wheel pants are an aerodynamic aid, reducing drag of the wheels a suprizing 
amount.  They also look cool. ;)
 

 
The plane would be expected to need slightly different elevator trim if you 
delete the wheel pants.  because the issue is a difference in coeficient of 
drag of the wheel, the effect will be speed dependant.
 

 
In essence you expect to need more up trim as the plane goes faster due to 
the landing gear not being retractable.  The wheel pants REDUCE the amount of 
trim change due to speed, but do not eliminate it.  
 

 
Retracts with close fitting doors that completely cover the wheel wells (like 
a full scale P-51) virtually eliminates the landing gear drag, thus 
eliminating a source of speed related trim change.
 

 
OK... there's the theory...
 

 
Practicly speaking, wheel pants have weight (can be a factor in meeting 
weight limit) and they can be a royal pain to keep on straight.  Some models will 
trim out fine with or without the wheel pants.  Some the trim difference will 
be significant.






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