RCU Forums - View Single Post - JetJoe OWNERS thread
View Single Post
Old 01-30-2008 | 04:31 PM
  #1507  
knobby1
Senior Member
 
Joined: Oct 2007
Posts: 237
Likes: 0
Received 0 Likes on 0 Posts
From: Sydney, , AUSTRALIA
Default RE: JetJoe OWNERS thread

ORIGINAL: Strykaas

Nice video. Those short plumes are a little astonishing. What's causing them ? Residual fuel is burnt after "injection" ?
Do you think that sustained operation ( # 10 sec ) is feasible ?
I'm no AB expert but the flame shape at low RPMs makes me think injection is sub-optimal at this point. Compared to real size turbine engines, flame shape is radically different. HIgher RPMs produce a better looking flame shape. I think there's still some optimizing margin in that area.
Hey Strykaas,

What you say is exactly correct, I expect it is "residual fuel" in the lines and spray ring. There is still a lot of development work to do, this was one of the very first test runs so I expected some shortcomings. The low rpm stuff which is what you mostly see on the video shows a less than optimal combustion, Jet dragsters predominantly use this as a "fire show".... as higher rpms are approached the shape and burn of the fuel is much better, more of a shortish blue coloured flame rather than a messy orange one, it's rather hard to see the "good" flame in the bright sunlight though, however, the ignition of the fuel at higher rpms is also less than optimal and is still a bit erratic. I believe a burst of 10secs or so isn't out of the question, mind you the amount of fuel consumed is enormous, so you'd need to carry quite a good supply...that little 3 min run on the video consumed just under a liter of fuel through the A/B...[X(] plus what the engine itself used.

I still have to sort the fuel burn quantaties as well so more work is needed in that area, I expect in a month or two, some tinkering and fine tuning she should be making all the right noises, then i'll post a decent video of it running at it's best, I should do a night time run too, that'll be interesting to say the least!

Cheers,
Smithy.