Hey guys I have another question.
sorry for the ignorance.

I currently have a airstart turbine which starts and runs flawless everytime. But do to the fact that I am getting a smaller airframe I am forced to get a smaller turbine with either an onboard start, or a full autostart.

Can someone tell me exactly what is the difference between the two?
thanks,
larry

There are a few different starting methods in use today.
Some of the engines use a starting scheme that requires you to apply a motor on a wand to the shaft nut in order to spin it up while regulating the propane before it will sustain on jet fuel.
Some others require a glow starter battery to be applied to the glow plug during the procedure.
Others are automatic, only requiring the operator to move the trim and throttle lever up in order to start the fully automated starting process.
There are as many starting schemes as you have fingers and toes, and I think that we tend to get lost in the semantics because of the variations, and how we use them in our language.
To me, "onboard start" when used in the same sentence with "full autostart" indicates a difference between two methods.

If you use these same terms independent of each other, they could be construed to mean the same thing.
I guess, in order to answer your question, "Onboard start" is a starting method other than "full autostart". It could differ from full auto in many ways.

Which small engine do you intend to buy?

Harley Condra
BVM REP
JetCat REP

Harley Condra,
it will either be the wren54 mk111 or jetcat p-60

I think you have to be careful with the wording too.

AMT used to call their start system "full auto start". And it was an air starting system. I don't know if they still call it that.

I personally divide the two different types as "air start", and "on board auto start".

And referring to AMT engines with a starter motor as such, "AMT with electric start".

Most the time you can refer to AMT engines as "back breaking support equipment", and those with no sense of humor won't laugh, but will know what you are talking about. I think Eddie Weeks "Auto start" weighs about 350 lb's and is carried (read as dragged) on a dolly to wherever he needs to start.

I've found that with electric start engines, (jetcat, merlin, artes, etc) that you can "manually start" them by regularing propane off board with no solenoid, and get smoother starts. I started doing this a couple of years ago, and have been preaching it to others. You're basically starting by the sound of the engine, same way the AMT air starts were doing, without having to bring a scooba bottle. Any problems and you shut the propane off right away, no more fire, so to speak.

Larry,

ALL WRENS turbines have the option of "onboard start" or "autostart" The difference in the two is simply what is carried onboard the plane during flight.

The "autostart" version carries all the fuel, and propane equipment as well as the glow driver onboard fulltime, so the plane is truly a fully autostart plane.

The "onboard" start version has the starter mounted on the engine, and the fuel valve stays in the plane. ALL of the propane equipment (tank, valve, plumbing) as well as the glow driver, does not.

The two engine have different ECU's, the autostart engine has a fully automated ECU, meaning, you slide your trim fully up, move your throttle stick to full then down to idle, and the engine goes through a full auto start sequence. On the onboard start, the ECU controls the fuel but the user controls the propane and glow.

If your plane will be weight or space sensitive, the onboard version is great, since you can leave off the items not needed for flight and save some weight and keep the install simple.

With the onboard start you can also leave the heavy 6 cell battery out of the plane and use a switch to control the starter motor. So actually you control the start motor, the propane and the glow.

Thats right!!!

Forgot about that one. What great little jewels these Wrens are!!

There is a little confusion about "Onboard start" on the Wrens, because "Onboard start" is short for Manual start with onboard starter (as opposed to Manual start with wand starter). It's a Manual start system rather than an Autostart, and means that you - rather than the ECU - do the start, switching on the glow and the propane etc. Once the start has been done, the ECU takes over. The advantage is that this system is smaller, lighter, cheaper and you don't need a starter battery or propane onboard.

Sara Parish
Wren Turbines

Hi Sara,

Sent you mail with a few questions