The most common reason for popping at idle in the JetJoe turbines is the lube line being a little too free flowing. Not a major problem unless it spits alot of flame. Does the popping go away above idle? If it does the lube is most likely the reason.

that explains a lot - Gabe told me that the new CC runs a lot cooler & also that the lube line requires a restrictor. The recommended restrictor is 22 gage hypo needle (~.016" dia.) I made my own & have experimented with a few different ID. I did notice that the fuel consumption is better with smaller restrictor size & that the poping is less. I will try a smaller size & let you know. This forum is excellent. We should keep it this way as supposed to all the bashing in the past. Thanks for all your inputs.

Do you think it could also be the reason for the hot spot? I will take note of this when I change restrictor size.

Yes it can cause a hot spot, not really a hot spot just where the excess lube is burned in the exhaust. If it goes away with the popping above idle that is what I would think it is. Don't go too small on the restrictor it can and will wipe out the bearings. I would rather one pops a little than ruin the bearings.

I had this popping in my Jetcat P80 and still does.. it runs great though !

I agree, i'd rather deal with the poping than replace bearings as this was just recently done. I replaced the restrictor last night to the recommended size & will try it soon. Will report on the results.

Yes the poping does go away when throtle is applied - so I think you've hit the nail right on. Also, the appearent hot spot goes away. The turbine runs great thoughout the rpm ranges & the temp is perfect. I run the 2-pc pipe & find that it works the best. ~490 deg at idle & ~590 at FT.

PROBLEM SOLVED...Thanks guys for all your inputs. The solution was finding the correct restrictor size for the lube feed line. I changed the restrictor size to .016" dia. & the turbine is now running perfectly. Will be installing it in a Falcon 120 shortly.

First flight on my Falcon 120 today with JJ1400. Engine ran perfectly Falcon flew great. You will love this combo.
Matty

Hey All,

Are the any JJ1800 owners out there?, I'll be getting one in the not too distant future and would like some feedback, good or otherwise.

I'll be using a Flightworks 400A pump to run it, will this be adequate?

Cheers from down under,
Smithy.

I have an 1800. It starts everytime. I have the semi- auto start version. I've only been able to get 105,000 rpms out of it. The specs claim 115,000. I think my battery is the problem which wasn't supplied when I bought the engine from Gabe & Mark. Even at 105,00 rpms, it's a very powerful engine.
Steve

Hey Steve,
Thanks for the reply, I'll be getting the "full auto fadec" setup, mine however won't be going into an aircraft, it will eventually be going into a 1/5th or 1/6th scale rail jet dragster modelled off a local car here, but thats a long term thing. I have designed a 316SS afterburner setup for it on paper, just have to wait until I have the engine so I can make sure all the measurements/dimensions are correct etc....then go about making it all work together. Fingers crossed!!

I'm expecting the EGT to rise slightly and the rpm to droop a few % when the A/B is operating but hopefully it won't be to drastic. I crew for a few "real" jet dragsters here in Aus and they have similar rpm droop problems accompanied by a small rise in EGT's, so one can only assume these little turbines will do the same.

Are you able to give me some approximate thrust figures and spool-up times, normal EGT's etc.. I'd really appreciate the info.

Cheers,
Smithy.

I've never measured the thrust. I have observed temperatures.
They are as follows:
Idle = 29,000rpms = 406 degrees celsius
Full Throttle = 105,000 rpms = 306 degrees celcius
I have it installed in a Mig29 with a bifurcated pipe and I would estimate approximately 16 - 17 lbs of thrust. That's a very ruff estimate. As I mentioned in an earlier post, I'm not getting the full rpms according to specs.
Steve

Hey Steve,
Many thanks for the info, your idle rpm seems a bit low, I was under the impression the the JJ1800 idles at ~35,000rpm, I stand corrected though! The temps seem quite low too, Jet-Joe quotes something up in the 630c range!? Maybe your bi-furcated pipe has something to do with it? The cooler the better, to a certain extent I imagine!

More questions if you don't mind, would you know the tail pipe outlet diameter? Also the outer diameter of the tail pipe mounting flange, the reason I ask is that I wish to manufacture a new 316SS tail pipe for it and need to know the approximate sizes etc. so I can order the materials asap, just trying to save a little time.

Thanks once again for your time,

Cheers from Sunny Sydney,

Smithy.

meps, your EGT's sound way too low, are you certain the EGT sensor is well inside the exhaust cone ?

Steve try checking battery voltage at Max rpm as the FADEC calibrates the pump delivery and uses the pump to increase rpms.

Paul

Hi to everyone and thanks for the suggestions. Mark ( Jet Joe Central) contacted me and gave me some things to check as well. I'm still amazed at the power this engine has. I'm going to see what I come up with this weekend after implementing all of your suggestions.You guys are great!
Knobby1, I'll measure both outlets of my pipe. It's actually a Tam pipe.
Steve

Thanks Steve,
I look forward to your reply.

Thanks in advance.

Cheers,
Smithy.

What could be causing the turbine NOT to spool up to full idle? My jj1400 will do this on occassion. The gas start & spool up is good to about 21k, then a sharp drop to 16k. Durring this time, it seems like the fuel is being ramped, but the rpm is very slow to rise & temp increases a lot. On several occassions, I would use a blower and the rpm would increase to running status. However, the last few attemps, it wouldn't even spool up to running rpm with the blower & I had to shut it down.

I check the bendix & it is working flawlessly. Bearings are new & in perfect condition. I may pull it apart to see if everything is clean internally.

Thanks

Make sure your battery is in good condition monitor voltage while starting. The starter motor could be not reaching full speed too, check and clean the oring on the bendix also check to see if motor has slipped in the mount and letting the bendix slip.

Anybody have a JJ1400 they want to sell?
I need one for an AMD Hawk I am building
Reply or send me a PM if interested
Thanks,
Matty

I have a JetJoe 1400 that I have not installed in my hawk yet.I had them both for sale a while back.Shoot me a pm if you are interested in the turbine.

PM sent

Hey Dave (rcguy!),

I've been having so much fun flying my turbine I've forgotten to look at the total time on my JJ1400. I promised I would report to you after 10 hours of operation, so here you go.

I checked it today after logging 7 flights yesterday and 5 flights today.

677 minutes = 11 hours 17 minutes.

My JJ1400 has never failed to start and give superb service (never once had to fiddle with my turbine...not even once).

I have it on a "jump on the band wagon" Falcon 120 (13 lbs. dry/16 lbs. wet). Very fun jet, but really no challenge to takeoff, fly, and land.

Rotates in less than 100 feet and lands sooooo slowly the brakes are not even needed.

I will definitely be looking for another scale jet this coming March in Lakeland, FL.

Greg Hames

Greg,

I will be installing my JJ1200 in a "Falcon 120'" that I have on order.
For me this is an entry level turbine trainer.
I am going to use a fixed U/C to keep it simple and light.

What type of retracts are you using if any?

I am using a set of Spring Air retracts (www.retracts.com). Just be sure to strengthen the mounting points for the gear with epoxy or Hysol.

You will not be disappointed with this airframe as a turbine trainer.

Very stable & easy to fly!

Greg Hames

Greg

This is just the feedback on operation needed here on this JJ forum. A few dozen more inputs on long term running would really assist. I'm committed now though on my MW's, the support being 5 star and won't go back.

Paul