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Old Mar 31, 2004, 02:12 AM
RPM
Registered User
Arvada, Colorado
Joined Jun 2003
124 Posts
Yellow Aircraft F-4

I have been contemplating purchasing a Yellow Aircraft F-4 and building it with a 17lb turbine. Anyone have any thoughts or suggestions.

I am flying at altitude so I think the output will be more in the 15lb range.
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Old Apr 11, 2004, 05:55 PM
An Aussie in Canada
Marty C.'s Avatar
Belleville, Ontario.
Joined Sep 2003
545 Posts
F4

I would of suggested a 12-15 lb thrust turbine, for your F-4 but I am unsure about the power losses at altitude hmmm. By chance do you know Dean Lassek? Dean is in Littleton Co. and he has many years experience flying turbines in your neck of the woods... I can give you his contact info if you like as he would definetely be able to advise.
Regardless the Yellow F-4 should perform really well on 12 lb thrust up, as long as you are flying from a good length sealed strip of course?
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Old Apr 12, 2004, 11:19 AM
RPM
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Arvada, Colorado
Joined Jun 2003
124 Posts
Marty: I calculated the thrust loss for a 70 degree day and I am looking at 14.25lbs. I think by the time I am done with the conversion the airframe will come in at 16lbs dry. I should be pretty close on the thrust needed. I will have to do some modifications to strenghten the airframe and wings. If your friend can give me any tips in that area I can PM you my email address to give to him.
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Old Apr 12, 2004, 11:38 AM
An Aussie in Canada
Marty C.'s Avatar
Belleville, Ontario.
Joined Sep 2003
545 Posts
turbines at altitude

RPM- yes please PM me your email address and I will forward the info on to Dean... I have sent Dean a link to this thread also, so he may well reply here first... Dean has been operating various brand turbines including RAM, JG-100 and recently TJT-3000 that I know of at the higher elevations found in Colorado. I have not discussed turbine performance losses at altitude with Dean before so I will be very curious to here what he has to say on his experiences.

By the way I should of mentioned, although we have not started work yet on model we also have a Yellow F4 awaiting turbine conversion from Ramtec-O.S. 91 D/F to TJT-2000 (15.5 lb thrust) turbine.
So far at a glance the planned mods over the F4 D/F version are for a new and stronger elevator pivot linkage set-up and also the retracts, currently it has Spring Air with wire mains, these will be swapped out for Robart oleos and BVM braked wheels. Tamjets have supplied a beautiful bi-furcated tail pipe also for our F4. Obviously fuel tanks should be upgraded as well, I think Gary Mueller of Jet-Tech makes larger capacity composite saddle tanks for the Yellow F-4, we will use these as the composite tanks although expensive, can save a model from fire damage in the event of a crash 'Ask me how I know' :rolleyes

Our Yellow F4 is the ARF version, there are a few strengthening mods to the airframe that could probably be incorporated also eg. use some carbon fiber cloth matting on floor section of F4 under engine this would help to strengthen wing centre section springs to mind... primarily upgrading servo's to high torque digital servo's on elevator and ailerons also would be suggested and also use of strong quality linkage horns and clevis's etc. on control surfaces...

Heres some pics. that may also help.
pic.1 is our F4 before removal of D/F
pic.2 is a photo i found on the web of a yellow F4 converted to RAM 500 turbine. You can also see the composite Jet Tech fuel tanks in this pic.
pic 3. is our ARF F4 pretty much as it comes from Yellow...
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Last edited by Marty C.; Apr 12, 2004 at 12:51 PM.
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Old Apr 13, 2004, 10:18 PM
RPM
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Arvada, Colorado
Joined Jun 2003
124 Posts
Marty, That looks very nice. I myself have been loking at the Jet-Tech fuel cells and I think that is the way I am going to go. I am still up in the air as far as pipes go, I am down to a Tam pipe and a PST turbine pipe. what is the diameter of the TJT that you have in the pic? My Simjet is 4.44", just tring to figure out if I will have less space in the fuse. I ordered my kit from Ed at Great Northern Models. It should be getting here within the next week. Roger
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Old Apr 13, 2004, 10:21 PM
RPM
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Arvada, Colorado
Joined Jun 2003
124 Posts
Marty, I was just looking at your pics again, can you enclose one looking down at your engine mounts and of your plumbing. Thought I'd ask. Thanks Roger
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Old Apr 14, 2004, 09:18 AM
An Aussie in Canada
Marty C.'s Avatar
Belleville, Ontario.
Joined Sep 2003
545 Posts
Pipes

Hi Roger, I have sent your email address to Dean, he should be in touch soon, if you talk to him he will put you in touch with other turbine flyers in your area.

Our Yellow F4 is still in the early stages of conversion to turbine. Sorry but no photo's of real use just yet. At this point we have only removed the D/F system and are currently beefing up tail linkage, still much to do.
The photo in my previous post is showing another Yellow F4 with turbine conversion that I found online (not ours) that photo shows a RAM 500 in the Yellow F4.

As for pipes we have one of Tam's bi-furcated pipes already for the F4 waiting to be installed... I will only use Tams pipes for all my jets... they are simply far superior in design, quality and performance to any other manufacturers generic size pipes that I have yet seen. Not only that but Tam will build you a custom pipe eg. bellmouth inlet and exhaust outlet diameters Tam will custom design to suit your exact choice of airframe and engine (thats why they cost a little more) this is even more relevent given your concerns with power losses at altitude. What size is your Simjet? a 1200??
Pipe design is Tams specialty. IMHO I would strongly suggest going with a Tam pipe you will not be sorry...

If you are dealing with GNM ask Ed about Trim wheels and maybe retracts to suit the F4 as they are top quality and great value also...
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Last edited by Marty C.; Apr 14, 2004 at 09:26 AM.
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Old Apr 14, 2004, 10:31 AM
RPM
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Arvada, Colorado
Joined Jun 2003
124 Posts
Marty,

Where did you find the photos? I am currently leaning toward the Tam pipe, I hear more and more about them every day. I can get the tanks and pipe from him for 500. That would save me some money in the long run.

My Simjet is a Sonic 8000 kit, It doesn't look like they make that model any longer so they call it a 1200aes, I think. Hard to keep up with the changes they have made.

I purchased Spring Air retracts and Trim Wheels & Brakes from Ed.
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Old Apr 14, 2004, 10:49 AM
An Aussie in Canada
Marty C.'s Avatar
Belleville, Ontario.
Joined Sep 2003
545 Posts
F4

Roger, try doing a search, using topic search on top left of page for Yellow F4 turbine conversion on RCU's jet forum http://www.rcuniverse.com/forum/jets/forumid_120/tt.htm
I think thats where I originally found the F4 turbine conversion photo a while back...With the retracts if you have not considered this already? I would strongly suggest installing Robart oleo struts all round, this is our plan as we also have the Spring Air units also. The functional oleos will assist greatly by reducing loads placed upon the retracts on landing...
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Last edited by Marty C.; Apr 14, 2004 at 10:53 AM.
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Old Apr 14, 2004, 04:50 PM
RPM
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Arvada, Colorado
Joined Jun 2003
124 Posts
Marty, I will definately be adding the oleo's. I didn't have any luck with the search on RCU.
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Old Apr 18, 2004, 09:23 PM
RPM
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Arvada, Colorado
Joined Jun 2003
124 Posts
I was informed today that the kit will ship in the AM. Hopefully I will have it by the end of the week.
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Old Apr 19, 2004, 10:35 AM
An Aussie in Canada
Marty C.'s Avatar
Belleville, Ontario.
Joined Sep 2003
545 Posts
F4

Roger, I just did a search on RCU for those pics. and could not locate them either hmmm! I would suggest maybe starting a new thread on RCU requesting pics. and info and see what response you have...

Did you end up buying the F4 ARF version or built up kit?

Have you spoken to Dean yet? When I sent Dean your email address he replied to me with the following-
[quote] A 500class engine is what he needs. Re performance loss, what we lose in thrust we seem to gain back "thinner air". The birds seem to fly just as fast. However, really hot days, 90 degrees F and higher start to take their toll. Still, I see no problem with the combo you told me about (12+ pound thrust class). [end quote]

Also let me know what you deside to do with the pipe as I can supply measurements of our F4 Tam pipe if need be...

Please post some pics of the engine and kit when possible

all the best-
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Old Apr 20, 2004, 11:49 AM
RPM
Registered User
Arvada, Colorado
Joined Jun 2003
124 Posts
Marty, I bought the Y/A F-4 kit. I will buy the turbine conversion from Tamjets which has the pipe and tanks. I think Electro Dynamics has a thrust limiter that goes between the reciever and the FADEC. I will equip the plane with this to keep the speed down. I really cant afford a wren at this point so I will go this way for now.

Dean has not contacted me as of yet.

I might start a build thread once I get the kit and begin construction.

I found some pics that Tam had posted on some of his Y/A F-4's If I find the link again I will send it to you. It was in Yahoo Users somewhere.
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Old Apr 20, 2004, 02:39 PM
An Aussie in Canada
Marty C.'s Avatar
Belleville, Ontario.
Joined Sep 2003
545 Posts
F4 Fadec

Roger, Iam not sure which version FADEC you have with your Simjet but with our TJT engines we use a FADEC AU-303, max rpm is user programmable eg. you can limit RPM/thrust so therefor you should not really need the speed limiter IMHO.
I have never felt the need for a speed limiter on any of my turbine models either the TJT-3000 (28 lb thrust) in my AD F-16, FC F-86 or T-500 (13.5 lb thrust) in my Cermark MB339. Dont forget you can always throttle back if need be... just my 2c worth on the subject
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Old Apr 22, 2004, 07:36 PM
RPM
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Arvada, Colorado
Joined Jun 2003
124 Posts
My FADEC is not programable. I was thinking the max speed sensor would be a good idea if it turns out to big time overpowered. I have no problem cutting the throttle back however, and this would be the way I will go if the power is not out of hand. Which I dont think it will be.

I also started looking at a Wren 54 kit which I think would be a nice fit into the plane. I will have to see what the budget looks like in the next couple of months.

Just FYI, your buddy emailed me today, Thanks
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