Best turbine for JMP Firebird??
10-17-2014, 06:31 PM
#1
Best turbine for JMP Firebird??
I am having to think really hard about what turbine to put in my JMP Firebird...It seems as though everyone is running a turbine that puts out around 50lbs of thrust and above! The thing is I want it to be fast but not 300mph fast. I have an AMT 280, but it seems that is a low thrust turbine for this plane. I would like it to fly well, but not be a rock on landing..So if anyone is flying with a 180 or below, please give some input on how it flies,lands and how long you fly for. Flight time is also important as I would like to be able to fly for about 10 mins. With that said, the K-210G looks like a good turbine for this bird with a fuel consumption of only 2oz more than the 180G. If anyone has any ideas or thoughts, please chime in. thanks
10-17-2014, 10:52 PM
#6
Try the new Jets-Munt M200XBL.... Weight to power ratio is awesome... You can always use dual rates for throttle and run on lower rpm (60% rate) and with a flip of switch get max rpm (100% rate) and power.... I call it afterburner switch....
Enjoy
Enjoy
10-18-2014, 07:21 AM
#8
I think the sleek design of the Firebird makes it very fast regardless of the turbine size. Back in the old days of Metropolis, IL Superman rallies I remember Firebirds with JetCat P120's - once up & on step they were still fast. Today I would say put a K210G in to keep the weight down vs. a heavy P200 or Olympus HP, etc. You can always turn the 210 down if you want, or leave it at full thrust and use throttle management. More power is always nice for take off & emergency go arounds.
Last edited by sc0tt; 10-18-2014 at 07:27 AM.
10-18-2014, 07:28 AM
#9
Keep in mind when that jet was designed the Olympus was a 45lb thrust engine. It also talks about the amt pegasus (280) in the manual. When I built mine I spent a lot of time talking with Tom about engines. In the end I put an AMT NL Olympus HP in mine but Tom said the pegasus will fly it "nice". Nice will still do 200mph easy in that jet. Victor montelbano in Texas flew a beautiful firebird with an AMT280 in it and it performed well. The reason I think people put the big motor in the firebird is typically you are not buying a firebird to have a "nice" jet but rather you want to scare your balls into your throat, set the world on fire and bring down moon with your sonic boom lol. If you have a 280 I would try it. See what you think. In a firebird reliability is the biggest thing. They don't glide well and IMO there is still no better engine out there than the AMTs.
10-18-2014, 08:01 AM
#11
Ok so if I answer the question correctly here as well, the question was what is the best turbine for a firebird. The true answer is the Olympus. The airplane, bypass and pipe were designed with that motor in mind. The bypass and pipe are optimized for that engine. Others will work but if you are looking at 45+ lb thrust engines I would use what was intended for that jet. Otherwise, as I said before if you already have an AMT280, for the flying it sounds like you want to do, I would just try that engine first.
10-18-2014, 11:45 AM
#12
Hi,
I had a mammoth in mine, and it was the fastest rc airplane I have ever seen, in person. Flying it aggressively, I had to set up to land after 4 minutes. I put another fuel tank in to extend flight times. Based on the criteria you gave, anything 160 and up will work for you. I think the 280 is too small, and will result in a very long takeoff roll, and lethargic response in situations where you want power now.
The Firebird has a high wingloading, and needs to stay on the step. It is the ultimate adrenaline rush though. Good luck!
Erik
I had a mammoth in mine, and it was the fastest rc airplane I have ever seen, in person. Flying it aggressively, I had to set up to land after 4 minutes. I put another fuel tank in to extend flight times. Based on the criteria you gave, anything 160 and up will work for you. I think the 280 is too small, and will result in a very long takeoff roll, and lethargic response in situations where you want power now.
The Firebird has a high wingloading, and needs to stay on the step. It is the ultimate adrenaline rush though. Good luck!
Erik
10-25-2014, 05:20 AM
#18
You need one of these
Specifications: M200XBL
Nominal thrust: 200N (45lb) at 115.000 RPM
Idle thrust: 7N
Idle RPM: 30,000
Diameter: 110mm (4.3”)
Lenght: 266mm (10,47")
Engine weight: 1.550g (3.3lb)
Installed weight: 1,680g (3,65lb)
02-21-2019, 07:57 AM
#19
Resurrecting this thread! Ended up going with the KT210 by the way and it does a great job while keeping the weight down...wondering what everyone is doing about the stabilizer servo since ours has the original multiplex giant scale servo installed still. Seems to be working fine, but it has to be at 15 years old, so I'm thinking about replacing it.
Also - anyone know offhand what the capacity is of the center tank? Couldn't find it in the manual and too lazy to go fill and measure :-)
Thx!
Also - anyone know offhand what the capacity is of the center tank? Couldn't find it in the manual and too lazy to go fill and measure :-)
Thx!
02-21-2019, 08:31 AM
#20
Hey Brian, or Scott, not sure who actually posts on RCU haha.
The Stab servo was the Multiplex Rhino as you know. Multiplex was bought by Hitec and while I can't remember the number, there is a hitec servo that is a replacement, it's still a multiplex servo, just in a hitec case. You are somewhat required to use this servo as the stab servo arm was designed for it. I know others have used the JR8911's or similar but it requires a different servo arm and clevis on the pushrod. Will update with the servo number once I know.
I just asked Tom and he says the center tank is 32oz, each wing tank is 66oz for a total of 164oz.
The Stab servo was the Multiplex Rhino as you know. Multiplex was bought by Hitec and while I can't remember the number, there is a hitec servo that is a replacement, it's still a multiplex servo, just in a hitec case. You are somewhat required to use this servo as the stab servo arm was designed for it. I know others have used the JR8911's or similar but it requires a different servo arm and clevis on the pushrod. Will update with the servo number once I know.
I just asked Tom and he says the center tank is 32oz, each wing tank is 66oz for a total of 164oz.
02-21-2019, 08:41 AM
#21
This is the servo I have in my firebird I believe, looks to be discontinued now as well 
There must be a replacement for it though.
https://hitecrcd.com/products/servos...-servo/product
Looks like this one is the same case size but lower torque at the same voltage, same torque if you run 7.4V.
https://hitecrcd.com/products/servos...-servo/product
There must be a replacement for it though.https://hitecrcd.com/products/servos...-servo/product
Looks like this one is the same case size but lower torque at the same voltage, same torque if you run 7.4V.
https://hitecrcd.com/products/servos...-servo/product
02-21-2019, 04:22 PM
#22
Hi Jeremy - It's Brian...
Thx for the reply...Turns out ours has a Multiplex Jumbo Digi installed instead of the Rhino. The Jumbo is half the speed and has 100 oz less torque than the Rhino. I looked at the HS-5765MH and it apparently has a 10mm output shaft. Guess I will keep looking. Also, we are using 6.6V RX batteries - I'm not so sure about using the HV capable servos with the lower voltages. Seems like maybe an accident waiting to happen being on the lower end of the acceptable voltage.
Thx for the reply...Turns out ours has a Multiplex Jumbo Digi installed instead of the Rhino. The Jumbo is half the speed and has 100 oz less torque than the Rhino. I looked at the HS-5765MH and it apparently has a 10mm output shaft. Guess I will keep looking. Also, we are using 6.6V RX batteries - I'm not so sure about using the HV capable servos with the lower voltages. Seems like maybe an accident waiting to happen being on the lower end of the acceptable voltage.
02-22-2019, 07:19 AM
#25
Matching that shaft on the servo arm to something else will be a *****. There’s some really good servos out there in aluminum cases putting out tons of torque but they all have standard size splines. The thing that has always bugged me about that set up is the single point of failure on the single most important control surface.
PaulD
PaulD
