Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Whiplash engine not getting enough air?

Reply

Old 10-11-2004, 08:25 AM
  #1  
JeffH
Thread Starter
My Feedback: (43)
 
Join Date: Jan 2002
Location: Carrollton, VA
Posts: 2,281
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Whiplash engine not getting enough air?

I have a whip with a K&B 7.5cc DF. I was flying yesterday in some very nice cool dry air. Wide open, straight and level, the engine would actually run out of air. It would start missing and cutting in and out. Would a ram-air intake tube help this? This would get the intake into fresh clean air.
JeffH is offline  
Reply With Quote
Old 10-11-2004, 08:05 PM
  #2  
Rudeboy
 
Rudeboy's Avatar
 
Join Date: Dec 2002
Location: Kortessem, BELGIUM
Posts: 3,508
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Whiplash engine not getting enough air?

You're sure you're not running it a tad too lean...? Or maybe you've got a fuel foaming problem at some point?

Because these engines have been sucking "dirty" air for years in DF planes, and it didn't seem to bother them too much.

Also, make sure you've got proper breathing room behind the carb. That can actually be an issue. Just last week I tested a pylon engine on my stand, and I got some really strange behaviour... apparently because the venturi was too close to my engine stand. The engine would almost quit the moment it got on the pipe and switched into the "scream" mode.

Maybe a pic and some detailed info about your setup would help out too.
Rudeboy is offline  
Reply With Quote
Old 10-12-2004, 07:47 AM
  #3  
JeffH
Thread Starter
My Feedback: (43)
 
Join Date: Jan 2002
Location: Carrollton, VA
Posts: 2,281
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Whiplash engine not getting enough air?

I know it isn't lean, it is about 3000 from peak when launched. If anything, it was too rich for this flight. Normally it unloads just right, but this time it acted funny. I have run this engine in fans as well on the whip. There isn't much room between the carb and the tank, about 1/2 of an inch. It might be sucking all of the available air out of the area quicker than it can be replenished at speed. Fuel foaming used to be an issue, but I solved that after the first flight.
JeffH is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service