Runs rich inverted? (102")  
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 >> Giant Scale Aircraft - 3D & Aerobatic >> Quique's Aircraft Support >> Runs rich inverted? (102")
Page: [1]

Login
Message << Older Topic   Newer Topic >>
Runs rich inverted? (102") - 4/26/2006 4:55:01 PM   
bdunsire


 

Posts: 161
Joined: 5/6/2005
From: camano island, WA, USA
Status: offline 		Greetings,

I have, I think, a solution to the problem coming to me from DA, but I am wondering if my problem is unique?

102", with a DA100 - just 5 gallons through the DA100, and as a result I have started to fine tune the needle settings. Got the transition from low to mid range to be cleaner than it had been - used to be sort of a rich four stroke type run until over half throttle. Leaned mixture screws just slightly, and got a clean run at the transition (tons o'power, my Yak weighs only 24 pounds - love it!)

Then, practising the IMAC roller (Advanced - 3 rolls inside in a 270 degree turn) - and I find the DA goes rich when I roll inverted, so I must add a small amount of power, then as I go upright, it runs well - must reduce power - hard to maintain steady everything in the roller with the engine running like this.

I tried straight lines - same thing - roll inverted, and the clean running engine goes slightly rich - this is while in level flight.

I am certain this rich running comes from the airflow into the carb. Pressure changes as I roll inverted, and talking with DA yesterday, they agree with my diagnoses. I have a solution being sent (just a few $), but I am wondering if others have encountered this rich running? (the big cowl?)

The carb is not in any direct airflow line, it is shielded (of course) by the cowl - but I do have it open under the intake.

Is this a unique problem? If not, other than the carb air flow blocking attachment I'm buying from DA - what is the solution?

Not trying to suggest this is a big deal - just something I have never encountered before, and something I have not heard of either with this plane.

Cheers,
Bob
       Post #: 1

RE: Runs rich inverted? (102") - 4/26/2006 5:47:11 PM   
Rezagh


 

Posts: 1810
Joined: 6/10/2004
From: Rancho Santa Margarita, CA, USA
Status: offline 		Hello Bob,

My plane personally is not ready yet so I don't know how it will be on mine but Quique has been running his on Cans with DA100, I didn't notice any problem. Are you running regular mufflers? BTW, do you have the updated wings on your airplane? If you are at 24lbs which is great you are probably running regular mufflers. Your diagnoses is right on the money. I have seen this problem happened before on different planes also. Once you install the airflow block you will be fine. I don't think this is a unique problem but I do think your solution is the best by using the airflow block. Just make sure you have enough opening and baffling to keep the engine cool and don't alter your cowl until you install the airflow block and see how it works out. If you still had any problem which I really doubt it would be the case, please let me know and I'll ask Quique to see if he has any suggestion. Quique won't be back in the office until May 9th.

Thank you,
Reza
Quique's Aircraft Support

_____________________________

Quique's Aircraft Company

(in reply to bdunsire)
       Post #: 2

RE: Runs rich inverted? (102") - 4/29/2006 4:39:09 AM   
bdbd


 

Posts: 57
Joined: 4/24/2003
From: Lilburn, GA, USA
Status: offline 		Guys,

I have the same problem but with a 3W 106 on cans with the trumpet. After talking to AI they agree it is an airflow problem. I am working on a way to slow the air rushing past the trumpet which is creating negative presure and at low throttle setting the engine does not have enough suction to overcome the negative pressure and starves for air. I have made a few extra cuts in the bottom of the cowl and plan to test tomorrow. If this does not work I am going to make a can larger in diameter of the trumpet intake which will force the air flowing around the trumpet to pressurize the area. I will keep you posted.

(in reply to Rezagh)
       Post #: 3

Page:   [1]
All Forums >> RC Airplanes >> Giant Scale Aircraft - 3D & Aerobatic >> Quique's Aircraft Support >> Runs rich inverted? (102")
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

1.078RCU1