UCD3D-60 Right & Down Thrust  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       

All Forums >> RC Airplanes >> Kit Building >> Kit Manufacturer Direct Support Forum >> Great Planes, TopFlite, Duraplane, US Aircore >> UCD3D-60 Right & Down Thrust
Page: [1]

Login
Message << Older Topic   Newer Topic >>
UCD3D-60 Right & Down Thrust - 7/17/2003 9:43:27 PM   
Volfy



Posts: 3227
Joined: 1/4/2002
From: Houston, TX, USA
Status: offline 		Hi,

I've installed a Tower Hobbies .75 on my UCD60 as shown. I really like the way the engine and muffler sit on the plane. However, being that the engine is tilted down roughly 30deg from horizontal, it's kinda difficult to dial in just right thrust. I get 1 deg. of down thrust for every 2 deg. of right thrust I put in.

Question: would a little bit of down thrust be bad for this airplane? Also, would the UCD fly okay with less than the 2deg. right thrust specified? I don't have a lot of room left on the firewall to offset the engine mount further, so I may not be able to get 2 deg. RT without the prophub being off the center thrust line.

Thanks.

Attachments
Click to see fullsize image.
Click for fullsize


_____________________________

Si vis pacem, para bellum.
       Post #: 1

UCD3D-60 Right & Down Thrust - 7/18/2003 8:40:55 PM   
Bax


 

Posts: 12619
Joined: 4/26/2002
From: Champaign, IL, USA
Status: offline 		Volfy,

You'll have to see how it performs. Downthrust is usually used to offset trim changes when power is changed.

One way to get an exact thrustline change would be to use an angled shim behind the mount instead of washers under the bolts. Start off with the kind of shim used in construction, and then sand it as necessary to get the amout of angle you need. That way, you can get the tilt of the mount in the exact direction you need.

_____________________________

Bill Baxter, Manager Hobby Services/Futaba Service/North America
3002 N. Apollo Dr. Ste. 1 Champaign, IL 61822 USA
Service Phone: 217 398-0007
Email: hobbyservices@hobbico.com

(in reply to Volfy)
       Post #: 2

UCD3D-60 Right & Down Thrust - 7/19/2003 1:05:06 AM   
Volfy



Posts: 3227
Joined: 1/4/2002
From: Houston, TX, USA
Status: offline 		Understood. I can slice the 7/8" thick plywood block (between the firewall and engine mount) on my table saw to get the exact right thrust I want. However, it's a rather permanent solution. I was gonna wait and play with the washers first till I get it right, but the 30 deg tilt is making it difficult.

I think I'm gonna just slice the plywood block at 2 deg. and be done with it. Now then, is it okay to shift the thrust line up or down 1/4" or so? Right now, one of the motor mount screws is interferring with the plywood mount bolts. I think I can adjust the cowl later on to recenter on the prop hub.

Thanks for the explanations.

Attachments
Click to see fullsize image.
Click for fullsize


_____________________________

Si vis pacem, para bellum.

(in reply to Volfy)
       Post #: 3

UCD3D-60 Right & Down Thrust - 7/19/2003 2:58:13 AM   
Bax


 

Posts: 12619
Joined: 4/26/2002
From: Champaign, IL, USA
Status: offline 		You don't have to make it permanent. Just sandwich the shim between the mount and the firewall and use the mount's bolts to hold it in place. Of course, you'd have to demount the engine if you needed to chang the shim.

As far as the thrust line is concerned, a small amount of movement one way or the other won't hurt it a bit. It may alter some of the handling, such as how the model couples in knife-edge and such, but that can be trimmed out.

Ideally, adjusting the engine's thrust line is so that you have the the plane balanced so that power changes alter the trim as little as possible. Some trainer type models like a LOT of downthrust, but some of the aerobatic types even use some UP thrust.

_____________________________

Bill Baxter, Manager Hobby Services/Futaba Service/North America
3002 N. Apollo Dr. Ste. 1 Champaign, IL 61822 USA
Service Phone: 217 398-0007
Email: hobbyservices@hobbico.com

(in reply to Volfy)
       Post #: 4

Page:   [1]
All Forums >> RC Airplanes >> Kit Building >> Kit Manufacturer Direct Support Forum >> Great Planes, TopFlite, Duraplane, US Aircore >> UCD3D-60 Right & Down Thrust
Page: [1]





Jump to:


Google 



Search | Marketplace | Event Calendar | Local Clubs | Magazine | Product Ratings | New Products | Discussion Forums

Photo Gallery | Member Video Posts | RCU Video Gallery | Instructor Search | Field|Track|Marina Search

Advertisers | Hobby Vendor Resources | Rate Manufacturers | Sign In/Sign Up

SITE MAP!   : :   FORUM RULES

© 2001 - 2007 24-7 RC, LLC, all rights reserved.

Charities we support that also need your help
Yorkie Rescue | Humane Society | ASPCA | Crohn's-Colitis America

Kaango.com Classifieds

0.390RCU5