I'm currently working on a 1/10 scale model 747 and C-5 gallixy. due to my quest to make these planes as much to scale as possible so I was thinking 4 turbines for each plane. I'm not shure exactly how much they are going to weigh, but it's bound to be a lot. I was thinking of turbines with any where between 12-50 lbs of trust. What do you think ?

The first question is - How much does the aircraft weigh with full onboard compliments? Next, if your planning on utilizing 4 turbines you'll divide your weight factor by 4 to determine the thrust needed for your aircraft. Remember that the AMA rules dictate a 1:1 thrust ratio. Simply put, if the aircraft's total weight is say, 20lbs, your turbine should not have a higher thrust value than 20 lbs. So, say your aircraft weighs 48lbs, you can go with 4
12 lb thrust engines, and so on. Hope this helps. Say, I'd love to see some pics of these babies - I'm sure they are quite impressive! Let me know if I can be of further help.

Todd

The actual AMA rules state that the plane can have a maximum installed thrust of 35 pounds, no matter how many turbines are in it, so with 4 engines each can have no more than about 9 pounds (roughly)

If a speed limiter is used, and the plane is limited to the manufacturers Vne (or 200 mph whichever is less) then the thrust to weight can be anything.

Matt

Mr Matt

Your right on that one. Forgot to mention the max. allowable thrust. Put me behind a turbine at full throttle and let me burn for that one...........

so basicly I'm limmited to 35 lbs of total thrust, but if I install speed limmiters to limmit the speed to 200mph or the manufacturres vne (what is the manufactures vne?) I can have as big of a turbine as I want?

dman

Your limited to 35lbs of thrust whether the airplane is 35lbs or 50 lbs. Your best best is two turbines of equal thrust on the two inboard pylons(Turbine A + Turbine B = 35 lbs). The rest of the engines would be dummies. You could also get 4 SimJet 700 turbines(7 lbs thrust). The other option is to build the plane as you wish, find a non-AMA site where they will let you fly, get your own liability insurance and go for it. However, this means that you would never be able to fly it at any of sactioned jet meets.


Turbine is in your court...

Ed

Dman,
I may be wrong-but I think ama has a Experimental wavier or something like that so you could fly your jet aircraft at ama fields-check the ama web site.



God Bless,Jackjet

Ok I just visited The AMA web site and through their links I got to the JPO web site; acording to their new waver proposil the max thrust is 40 lbs for a single turbine or 50lbs for multiple turbines, but this is for a level 2 waver and thats as high as they go with it.
I was just thinking that there might be someone from the AMA I could set an oppointment with I could mabie get a higher waver if I prove I can fly the aircraft safely, via a demo. Let me know if you guys know of anyone I can contact.

I am curious also. I am thinking of a twin project, using two P-120s, but it seems I will have to detune them to 17.5 lbs each. This seems like a waste of engines. Is the current AMA rules set a Max 35 lbs or 50 lbs?

Sung

Here in the UK we don't have a max amount of thrust that is allowed.
My Aviation Design Mirage weighs 22lbs and has 30lbs of thrust.
My Avonds Rafale weighs 15lb with 20lbs of thrust.

Mick

Dear Rojeck,
Lets see if I can set you straight on the facts the official AMA rules are (as far as I have found out) are a 1:1 ratio of thrust if your aircraft weighs 20lbs then your total thrust is limmited to 20bls of thrust combined (total combined thrust from all turbines) with an absolute total thrust of 35lbs, no matter how much your aircraft weighs. Now you can ubtain a waver (please visit the JPO web site for full details.) for additional thrust and according to the jpo's new proposal there are two leves two the waver at level 2 you are limmited to 40bls of thrust for an individual turbine and a total of 50lbs for multiple turbines. Again please visit the JPO web site and if you like print their turbine proposal it's 7 pages long.

But as for me I would still like to know if there is someone I could contact for a "higher" level waver.

First, the JPO is working on rules changes, as far as I know they are not about to be adopted any time soon, so you can go by the latest AMA waiver rules, dated July 9, 2001


1.) All planes are limited to .9 to 1 (dry) thrust to weight ratio, based on INSTALLED thrust, unless.....
2.) An approved speed limiter is employed, in which case the thrust to weight can be anything as long as the speed is limited to the manufacturer's Vne, or 200 mph, whichever is lower
3.) In no case can the total thrust of ALL motor(s) be greater than 35 pounds total.

Matt

PS I cannot imagine the AMA giving out waivers for higher thrust at this point.

thanks for setting the facts straight mr_matt. i'm not shure weather or not the jpo's proposal has been approved or not and at this point dont much care. mabie I need to move to the uk?JK

JK

Don't move east, just north! We're much more lucid up here. May be it has something to do with spending half the year inside where it's warm?!

Ed

by jk i ment "just kidding" is one of the things I've picked up at chatrooms my real name is Darain wich makes my first initial D...hence dman and 80601 is the zip code of the closest city to where I live therefore dman_80601 and my email is [email protected]

Ok, Sorry, Looked like a signature.

So when are you moving North?
Ed

Ed

I don't know when or if I'm moving anywhere but just in case I'd like to know your regs for turbine powersd aircraft


Darain