funflyerf4

My Feedback: (6)

Any thoughts about this combo? I was planning on going with the Bee but wen't with the Rabbit.After watching Dominics build I gotta get mine started and built.




Frank

joeflyer

My Feedback: (48)

I hope you're planing on dialing it down. That's way too much power for a Yellow F-4, the Bee would be a better choice. Your biggest problem will be finding room to carry enough fuel.

Joe

kevinthoele

My Feedback: (1)

I have flown them with Golden West, AMT 180, Jetcat P-80 and Jetcat P-120. Just put a K-80 in old one I have and will fly soon. The light ones fly better. You need 15 degrees flap for take off and none for landing. elevator gets too soft with flaps on landing. I have 5 tanks totalling 77 ounces in mine.

roger.alli

Wow,,

I briefly owned a Yellow F4 powered with a OS 81DF. It flew fine (for a ducted fan) . Probably had 6-7 lbs static. Yellow recommend a 5 ¼ fan and a model weight of 11-13 lbs.. I could not comprehend a Jetcat P120 in one.. Are you sure we are talking about this model.. http://www.yellowaircraft.com/jets/f4.htm

Roger

Shaun Evans

Hi,

I've flown it on a P-80. Only difference with a 120 would be more thrust. I do think the P-60 is ideal. I haven't had first-hand experience with the P-100 yet, but I imagine that would be the best engine for this plane. I agree with Kevin on all points.

HarryC

My Feedback: (1)

I have had a Yellow F-4 with 14lbs thrust. It does not have flaps and I don't see how you could get something like a P-120 in it, plus the weight of something like a P-120 and its fuel load would be ridiculous for that little wing, and the undercariage mounts and wing skin above the mounts just wouldn't take it for long. You must be talking about a different model. The Yellow F-4 has to be made as light as it possibly can be.
H

kevinthoele

My Feedback: (1)

Yes It is the Yellow F4

kevinthoele

My Feedback: (1)

Latest Pic with K80

HarryC

My Feedback: (1)

Who thought it was a viable idea to fit a p-120 into a 44" span model weighing around 15lbs? And was there any space for fuel other than enough to taxy out to the take off point?! I fitted a PST600 of 14lbs thrust and struggled to squeeze in enough fuel even with custom made saddle tanks either side of the engine and another tank between the intakes. At around 16lbs weight it was a lead sled.
H

LGM Graphix

My Feedback: (22)

Back before the smaller engines were available it was not uncommon to see RAM750's stuffed into all of these airframes. Same size and weight as the P80/P120. Had to use a big hammer to get them in, and flight times were short as you couldn't fit a ton of fuel in, they were heavy etc, but they worked Before the RAM's it was the old Sophia's and JPX's, the Yellow F4 was tight, but the BVM F16 was really tight!

Shaun Evans

Yep,

Stuck a Ram or a P-120 in just about every Yellow jet...

rhklenke

My Feedback: (24)

That is THE definition of an F-4...

Bob

kevinthoele

My Feedback: (1)

Had all that it needed for 5 minute flights. There is a left stick use it. At vertical climbs full throttle was great. I have over 6000 flights on multiple yellow F4's so I know what makes them work. I think I have flown 10 in all and this one is almost 10 years old.

HarryC

My Feedback: (1)

I'm just gobsmacked it flew at all with that weight in it. Are you sure it was flight and not a ballistic trajectory? I fancy getting another one but based on the handling due to weight in the one I had I was thinking about a Wren 44 of 10lbs thust and low weight and small fuel load, and a straight pipe not bifurcated. The thought of it with the weight of a P120 and associated fuel does not give me a good feeling. It's not that I don't cope with high wing loadings and high landing speeds, I am used to flying an F-104, but my YA F-4 would not have been improved by more weight!
H

kevinthoele

My Feedback: (1)

If you were going to build new yellow F-4. A P60 with bificated pipe would be the way to go. It would be light on landing and fast at full throttle.

HarryC

My Feedback: (1)

One problem I had was that the bifurcated pipe seemed to cut a huge amount of thrust. It didn't fly like a 17lb plane with 14lbs of thrust, it flew like a 17lb plane with 8lbs of thrust. It was a Tam's pipe for the YA F-4, I couldn't get a reply from Tam on what gap to use between engine and pipe so went with the engine maker's recommendation. I don't have a test rig to try it on but it felt like a massive reduction in thrust. It was also extremely loud. That's why I felt like trying again with a single pipe and cutaway the underside of the tail if I can get my hands on another kit. What gap do you use and have you found the pipe loses a lot of thrust?
H

Shaun Evans

Hi,

Do you remember what the gap was? You can lose a huge amount of thrust with the wrong gap, that's for sure.

HarryC

My Feedback: (1)

it was about 25mm I think. Couldn't get an answer from Tam so went with what PST engines recommended

kevinthoele

My Feedback: (1)

There must be something wrong with your set up. I got 130/140 with a golden west at 8 lbs thrust in my first one.