ChrisPetersen

My Feedback: (3)

What constitutes a wet start? Yesterday I fired up my Yellow F15 for the first time and it shot about a foot long flame out the pipes for about half a second. Yes I did purge it , yes I apparently missed an air pocket, yes I did just let it work its way out, no in hindsight, not a good idea (it did look very cool though). I let the p120sx run for a few minutes to get my Dr recommended dose of turbineosis out of my system. After I shut it off and got done patting myself on the back, I noticed some blueing around the pipe. Well after some very articulate use of “colorful metaphors” strung together in a series long enough to make a Marine blush I took it back apart and got some pics. I don’t want to fly a plane with a pipe problem but on the other hand nobody wants to waste money they don’t have to on a new pipe they don’t need. I think the pics. make it look worse than it really looks . There is a small wrinkle underneath the blued area I tried to capture with the camera. Is this pipe safe?

ChrisPetersen

My Feedback: (3)

Here should be the pics

FILE IFR

How close is the pipe's bellmouth to the engine's nozzle?

Proper pipe alignment goes a long way too.

Got a pic???

ChrisPetersen

My Feedback: (3)

I dont have a picture that has the turbine to bellmouth gap and the plane is still apart till I figure out what to do now. But the tubine is slightly inside the bell mouth. I contacted jetcat when I built it and tried to stick to what they said as far as gap but it is out a little further than they say to do. On alignment I was kinda proud how the alignment looked but it obviously has a hot spot.

I-NAV

My Feedback: (3)

Looks like the pipe tried to collapse on itself where the double wall starts. Most installations use around 20mm from the edge of the engine exhaust cone to edge of the bell mouth to allow cool air to mix with the eflux. I'd replace the pipe. The Yellow F-15 is too nice a bird to risk.

FILE IFR

I would too.

In the world of opera singers, Individuals with 'Golden Pipes' are held in high regard... In the world of RC jets, it's just the opposite.

molo_30

Throw the pipe. Get a new one and then you don't have to worry.

If you think its going to be ok, ask Andy Andrews on here what happens with wet starts!

Wayne22

My Feedback: (2)

I would not fly with that pipe... Compare the cost of a new pipe to the cost of the airplane that your are risking...... sure you might get another half a flight out of it, or maybe even nine and a half flights, but in the end it will be an expensive way to save $300 or so......

ChrisPetersen

My Feedback: (3)

I wont risk my plane on this pipe. I have been considering other uses for it though. Perhaps a $350 vase? A pencil holder?
Now its got me thinking though, What kind of gap for the turbine to tail pipe? Jetcats manual says stick that sucker inside the pipe. But not many builders do it. is that to avoid this problem? I am sure the flames did not help but maybe with no gap I gave myself less margin of error as far as cooling goes . If I am gonna have to get a new pipe at least I want to learn something from it.

trioval00

My Feedback: (17)

I asked the same question . and here is the reply I got from John Redman. and it was for my P-120.

Mark



Hi Mark,

Keep it with the range of 3/4 to 7/8 of an inch separation. This gives the best airflow to not hurt thrust and keep the tailpipe as cool as it can be during operation.

John

ww2birds

My Feedback: (14)

Hyrumflyer,

I lost a Yellow F-15 this summer due to pilot error (ugh!). I replaced the original pipe with a Tam pipe since I was using a 160. I have the original pipe that I ran maybe 10 flts before the swap. It's yours with my compliments if you want to pay for the shipping. It was a good plane and I'd love to see someone get some use out of the pipe...

If you do decide to go with a new replacement, consider the Tam pipe. They are absolutely beautiful. Charles' pipes are very nice, no issues, but the Tam ones are works of art...

Agree with the other comments, you need at least an inch (25 mm), I believe 30-35 mm is better. I have some pics on the Yellow F-15 ARF thread with my install here:

[link=http://www.rcuniverse.com/forum/fb.asp?m=8533533]http://www.rcuniverse.com/forum/fb.asp?m=8533533[/link]

Dave McQueeney

ChrisPetersen

My Feedback: (3)

Thank you Dave. I sent you a message in the pm box.

lov2flyrc

My Feedback: (24)

Well done Dave!!! [sm=thumbs_up.gif] Nice to see guys helping each other out. You got a Dreamworks hat coming to you, well deserved.