Jetcat P-40?
 

Jack,
I'd have to agree with ET on that one. Its like any other plane, the weight is relative. Add a pound or two to a 20 pound plane and you may not even notice it, but add the same two pounds to a 12 pound airframe and you will indeed know the extra weight is there!

When I built my Reaper, I had it at 19 pounds dry, then went on a diet and now its about 16.5 dry. Made worlds of difference for take offs.

As for power to weight, I am flying an 18 pound (wet) jet with 12 pounds thrust, no slouch at all as you would see in take off and climb. I can easily fly the pattern at 1/3 throttle without any trouble. I am sure putting a 20 pound turbine would liven it up but it is totally not necessary IMO in sport jets. As for heavier wing loaded scale jets, I cant comment - yet..

AJC

Jetcat P-40?
 

One point that I don't see mentioned yet, regarding the use of a (detuned) large engine in a small plane... residual thrust !

When I changed from a RAM 500 to a P120 in my std Bobcat, we were almost unable to land it without resorting to killing the engine. That's because the bigger engine had much more residual thrust at its lowest permitted idle speed than the little RAM had. Instead of being able to land the aircraft clean, or with flaps, I had to change the setup to use reflex in order to get enough drag to offset the extra thrust.

Gordon

Jetcat P-40?
 

Would you like to share with us which one you chose?

large turbine-derated
 

AJ & GordonMac,

how this-we can use say a 28lbs.thrust turbine turned down to 12lbs-and use flaps-speed brakes and a homemade thrust reverser to slow it down when landing-I KNOW it can be done as I had one on a Byron BD-5 in the 1980's-and it really did work even on a DF setup-I know what you are saying about the weight-but for me-it just does not matter that much-I had a JHH F-86 and it started out with a Turbax and K&B 7.5 -12.5lbs. with 24 ozs. of fuel at take off - it flew ok - around 120mph - landed at 26mph - (checked with radar gun) - also I had a FULL intake liner in it and variable exhaust nozzle that Paul Ivie desgined- but when I installed the OS.91 and Dynamax - then it was 15lbs. with 32 ozs. of fuel - it would go 160mph - that's a LOT more speed - the landing speed was 30mph with 40deg. of flaps.- the extra weight was offset by the LARGE increase in power - as far as fuel - I could fly it for a solid 10 mins. - because I would throttle back. Flew very scale. I know we can do the same thing with a turbine powered model.

Jackjet

Jetcat P-40?
 

Yeah, but how would your JHH Sabre have flown at 8 pounds with a 45? A totally different animal.
Gordon pointed out the obvious that we all missed, the residual thrust issue. A thrust reverser? That's what we need...additional tailweight!
Again...the expense and effort needed for a plane with a seven pound thrust turbine is a lot less than a larger one. You can ditch the brakes, and the expense and weight of them, you can use cheaper servos...you can build an all-balsa airframe, and monokote it...
You could have a JHH Sabre airframe into the air for $500 or so. Weighing maybe nine pounds, tops.

Smaller turbines
 

My personal taste is smaller planes. I just couldn't see packing a 22lb thrust turbine in my Sport Shark! Like previously mentioned, I think it's neccessary to match airframes with power plants. On the other end, I couldn't see two JF50 Bees, in a Fiberclassics Mig 29! But them again, I really shouldn't say because has anyone tried it? LOL!
Myles:D

Simjet 1200aes
 

Hi Ed,
Wait untill you see my AV8R with my 1200 on it .This is a neat airplane.I covered part of the tail with .0015 sheet aluminum in case of a hot start.I should be able to test fly before superman.

AV8TR with 1200
 

Hi Vic

Can't wait to see it.

Ed

wren
 

I put another 5 flights on my Reaper with Wren MW54 on it this weekend, I am allways amazed each time I run this jewel of an engine!

I know the autostart version is available with the new starter and orbit ecu (pretty sure its orbit) but the semi auto like I have is easy enough.

I totally recommend a Wren 54 to anyone wanting a smaller turbine. But that PSTJ600 looks great too... soon we will have TOO many choices!

Andrew

large turbine-derated
 

[QUOTE]Originally posted by EASYTIGER
[B]Yeah, but how would your JHH Sabre have flown at 8 pounds with a 45? A totally different animal.
]

Easytiger,
I tend to build them a little strong-so I would never build them (if the plan says use 1/8" ply to make a former-I use at least 1/4",etc.) - that light anyway-but like I said before - the extra weight does not bother me at all-plus I can fly in windy conditions that keep other jets grounded.


Jackjet

Split thread
 

Since this thread had taken on a split personality, I have split the thread in two. All posts relating to the smaller class turbines have been left here (since that's what the thread was supposed to be about!), and the posts dealing with Spiderjets have been put into a new thread:

http://www.rcuniverse.com/showthread...652&forumid=26

Regards,
Gordonn

So is Tom Cook selling the PST turbine???
 

So is Tom Cook selling the PST turbine??? If not why?
Chris

JMP and PST
 

Hi Chris,

PST is setup to distribute through some independent dealers and the global TJT sales force. When TJT and JMP decided to split, the PST distribution left with us.

Even if you're not ready to buy one and you just want info to compare engines with, send me an email and we'll yak a bit. I'm always willing to talk jets... :D (Of coarse If someone want's one, I can help put with that part too...)

The PST is ready and flying all over the world, but not widely sold into the states because of the AMA issue. I am writing the application, so that shouldn't be an issue for much longer.

Thx,
Kelly