on the first start of my ram 500 in a new maverick it seemed to have trouble stablising the idle rpm going from 35k to 65k, finaly after about 15/20 seconds it sorted its self out and seemed to run fine. Is this how they are? is it sorting its own pump settings for a idle? is it one of these fuzzy logic things which optimises its self?
Also the temp probe is picking up radio freq ( im on 35 meg) and making aa mess of the rpm reading so when the engine is sat on the work bench and not running and you switch the sytem on and the tx is near the engine ,temp probe or start box the egt shows 900 deg and goes into cool down. I have isolated everything and even tested without the engine atatched and it does the same when the tx gets within 12 inches of the egt sensor. I have cured it by winding the egt sensor wire round one one of those torodal round things 12 times and seems ok but something aint right, any ideas??

Thanks
jason

Jason

You will get all sorts of "ideas and suggestions " here. Rather than waste your time call / email / write the factory direct regarding your particular circumstances. Mr. Bob Price was the designer of the ECU and would be very interested in addressing your concerns.

Regards

Dean Wichmann
RAM District Manager
Canada

Jason,
You posted something very similar to this on the 27th of March saying that you were picking up interference from you transmitter that was affecting your temperature reading. I agree completely with Dean. Get in touch with the RAM factory and tell them what the problem is and let them solve it.

Ive spoke to Bob Price and ram about the temp problem and they don,t know whats causing it.I am trying a new ECU soon but Bob Price seems to think this will make no diference as it,s working ok other than that.So, It's a long shot but Just hoping someone out there may have Idea what`s going on.

Hi Jason,
By now you may have noticed that some folks are very sensitive about problems with some turbines...... Dont worry, many other brands have their own problems too.
The problem you have is caused by poor RF suppression on the EGT probe amplifier. This amplifier has to amplify a very small signal 20 - 100mv DC to something the ECU can read. This makes any AC external signal imposed on the leads cause an error if not "shorted". The torroid you used for the cable has the effect of short circuiting the AC (RF from your TX) before it gets to the amplifier. Here is an even easier solution that should have been on the PCB of the ECU. Remove the cover from the EGT probe plug and using the terminal screws that hold the wire, put a disc ceramic capacitor of 10 nanofarads across it. If the problem persist put another one of 1 nanofarad in parrallel with the 10 nF one. If this failes to improve the problem you most probably have to live with it. Let us know what you find.

Turbojet

Ideas? Yes, indeed. I am very puzzled why you insist on laying the Tx virtually on top of the EGT probe. This is NOT a valid condition. When you are flying, the Tx is a long way from the probe. You are probably picking up some harmonics as well as overloading the ECU with a massive signal. Does the system work when you are standing 10 feet away with the Tx antenna down? If so, I see no problem here.

I think I pointed out before that I have some planes that go crazy when I lay the Tx antenna on the wing or fuse, and that this makes no difference at all in how they operate in normal situations. These planes range check just fine, and of course fly just fine.

Do you start your plane standing 10 foot away from it? I dont and wouldn`t, a bit dangerous wouln`t you say?. When I stated 900 deg that was with the aerial down and the tx near the engine , ECU or start box, if the aerial is up the egt is efected at anything less than 5 foot away and that to me aint no good.

jason

I can confirm it he is having aggro with his engine, he wants to fly it with us on Sunday....He wanted some help from people that have Rams, just hints and tips....
Thought this was a hobby where you help one and other out not have ago at each other!

You are right this could be an informative thread, like the explanation Turbojet gave , no bashin just an explanation from somone who is more qualified to comment the majority of us.All turbines have problems but it does seem that some people who may have connection with certain manufactuers would rather a discusion like this did not exist on these discusion forums.


jason

P.S have you run the jetcat yet?

No Jason I have not run it yet because I don't pick it up until Toledo. Im going wednesday for a week. Bunch of stuff to do there. Bkf

Welcome to earth. Sit a spell, Take your shoes off.

Jason,
I am sorry for my ealier post, I was unaware that you had already spoken with RAM about this situation. Have you tried to see what happens with different radio bands, i.e 50mHz or 72 mHz?

Patrick.

Jason's "location" details state that he is in England, not the US. Last time I was in the UK, only 27 & 35 Mhz were available for R/C aircraft use there (and 27 Megs was so infested with illegal CBers that it was to all intents & purposes unusable for our R/C aicraft use), so 50 & 72 Mhz would not be an available option unless things have changed since then.

Other R/C frequencies within the 35Mhz band might offer some relief though.

Gordon

We can't fly on 50mhz or 72mhz, but that could be the answer.
35mhz still!

I do not use any other band other than 35meg although I have tried our highest and lowest freq with no change. When I spoke to Bob Price he said that he does not own a 35 meg tranny so hasnt checked the ecu on this band but there are people in this country flying with ram engines who are not experiencing the same problems but I don't know if there's is a "X"series ecu like mine or not,although Bob says the new ecu has only minor changes to the ramp smoothness etc and nothing has changed that could cause my problem.
I did a range test yesterday which was excelent with the engine running and not so I will test fly it this weekend with the toroloid thing fitted as this seems to sort things out and see how she goes.

jason

Jason,
Just for info, I have flown my RAM on 72 Megs at FJ and here in Australia I use 36 Megs, pretty close to the UK 35 band. My RAM ECU (latest version) is faultless so long as I charge before every start to ensure the voltage is at least 7.6
I dont think the ECU is incompatible with 35 BUT you never know, Good luck,
BRG, David.

Jason,
I don't know if you have thought of this or not but this could be a simple work around to your problem. since you get good range test with the engine off and running just keep your transmitter a foot or two away from your engine and start it using the engines start box. I know this doesn't solve the overall problem but it will keep the interference from happening and you can fly without any problems.

Patrick.