Scale Soaring UK

Hi all,

looking to pick an engineers brains! I'm going to make a self starter for my DLE170, just because.

I've nicked the idea from MVVS, and using a bendix starter from a scooter it should be very easy to implement, I just need to know where to look for the gear ring that mounts to the prop driver - any ideas? Obviously I have to find the right pitch to match the starter but any clues to get me off and running would be very welcome.

Cheers, Ell.

Elliot

FEMA do a number of different on board electric starters and list the gears separately.
http://www.fema-modelltechnik.de/Neue_D ... 14_eng.pdf

John M

Interesting the way FEMA is using a spragg bearing in the main toothed prop freewheel, does away with old fashioned Bendix method, very neat..

Antonia -(from her hospital bed)

Antonia -(from her hospital bed)

Get well soon...

BC

I'm not mad keen ob the one way bearing system, it's fine if the bearing is in an oil bath, but anyone with a zenoah spring starter will know the horror of a dry bearing if it's not regularly lubricated...

The MVVS bendix system is simpler to implement and obviously disconnects drive when done, I just need to find the appropriate drive gear.

Get well soon Antonia, hope it's nothing serious.

Ell.

Elliot,

Not sure if you are thinking about a singe gear set, but you may struggle with that. The motor will have to be huge. The commercial ones have about a 50:1 reduction.

I have the clutch bearing on my Z62 starter, greased with the correct grease, and it has been on about 3 years with no problems. (Yet!!)

Your big motor will take some turning over.

BC

Barry, it's quite a pokey starter, I've bought one for a 50cc scooter to make a starter for a DLE 55 or MVVS 58 - whichever looks most useful at the time.

I'll attach a couple of pictures so you can see what I'm on about, much, much simpler than the EME system (essentially a FEMA copy).

the starter itself has a couple of sets of reduction gears I think, then the reduction onto the big prop driver.

Unfortunately, the driven gear onto which the bendix engages seems to house an integral clutch mechanism on modern scooters, not like in my day, ooh my back, have you seen my teeth, I only put down a minute ago etc. etc.

Ell

the starter arrived today, it looks perfect, just need to source that starter ring...

Elliot , I have two models fitted with Fiem starters , my two thirds scale WW1 Hanriot (400 watt ) and my two thirds Scheibe SF33 motor glider 250 watt
I made the ring from 1/4" by 6" bar dural 6082 T6 , cutting the teeth on my milling machine with a rotary table using an involute mod 1.75 mm no 2 cutter. The teeth seem to be standing up to the starts ok . Battery is from Stephans Lipo Shop Quantum SLS 4S 65C 5000MA with XT90 CONNECTOR
i have a 90 amp automotive relay operated via a microswitch on a d shaped servodisc/servo plus a manual switch breaking the coil circuit
Need to be careful , lot of power available , KEEP BEHIND THE PROP WHEN BATTERY CONNECTED
The SF33 has a King 190ccflat twin , 16 teeth on the Fiem and 90 teeth on the motor gear, hope the above helps

Hi Ian,

thanks, that's really good data. It might get to the stage where I'm badgering engineers to make me a ring, surely there must be source already? I'm thinking go-cart drive sprockets... thanks also for the cutter info.

I'll let you know how I get on

so, I managed to find a crown wheel, from a 200cc Simonini paramotor!

It's fractionally smaller ID than a DLE111 prop driver OD, so, as that's the engine I'll be using as a test bed I've got a good plan to make it fit, just need to up my lathing game and possibly buy some more cutting bits...

i've now spent just over £100 on bits, but feel it will be a much more satisfactory starter assembly than the one-way bearing jobs, also I don't think anyone makes those for the DLE 170.

More soon, Ell.

Like this~??

http://www.austars-model.com/dle-170cc- ... 13313.html

BC

BC, yeah, I've seen that one, it's horrendous. Plastic gears all over the shop.

You know how often a car starter motor assembly fails? almost never, that's what I'm after.

The EME one way bearing system is neat, but still not cheap or robust - MVVS and ZDZ have the right idea, I don't understand why it's not more often adopted.

Ell.

I didn't say it was good, just available....



BC

Elliot , enclosed photo of the Fiem starter fitted to my two thirds scale Hanriot WW1 biplane. The alloy starter ring is fitted to the front of the steel reduction drive pulley which is mounted on the JPX crankshaft .
My tig welded home made steel silencer has a half round cutout in the top surface so that the Fiem unit can be mounted below the motor which works well and sounds good. I hope detail helps and good luck with your unit

Thanks again Ian,

out of interest, do you use a relay or or microswitch for your starter?

Ell.

Elliot , I use a Burgess say 10/15 amp micro switch which is operated by a "D" shaped servo disc/servo which is wired into the coil circuit of a 90 amp auto motive relay . Additionally I add a hand operated safety switch switch (Apen switch ) on the model which breaks the coil circuit.
I also have a second micro switch/servo for the ignition with a small 6 volt buzzar which sounds when the ignition is on/live.
The choke is also servo operated .
The above are available from Farnall or Radio spares.
I use XT 90 connectors for the start battery and leave these disconnected until the last moment .
The Lipo start battery is mounted in a wooden tray which has a tongue at the front and a "wing bolt " so that the battery/box can be secured in the model but easily /quickly removed for charging/storage .
Recommend a good quality high C rated Lipo start battery .
The main thing with an on board starter is that you need to develop a safe routine when using the starter and stick to it each time , don't be rushed or distracted , keep every one behind the prop and your helper needs to fully understands exactly what you are doing.
Good luck and be safe

Thanks again Ian, you're very kind!

I have however cheated... i've bought a 100 amp starter relay like this:

https://www.rapidrcmodels.com/electric- ... 4807-p.asp

Just need to get the prop driver on the lathe and mount the starter ring next, I'll let you know how I get on.

Ell.

Elliot , it (the relay in the middle of the unit)looks very similar to the relay I use , neat idea and reasonable cost , something to remember/use on next project .

I retrofitted and modifed an EME type starter to a hybrid DA100 I rebuilt. It worked perfectly for many starts, I eventually put a larger motor in the model, the elec start 100 was shelved waiting for a suitable model. A mate needed a motor for a secondhand Yak he bought so I "loaned" it to him. It was fine for a few dozen starts, then the sprag bearing failed in flight, which stopped the engine and tried to twist off the installation as it tried to back drive the starter.

It may have been that his unbaffled engine installation caused it to get too hot, it may have been the bearing quality. I rebuilt it and fitted a nice german made sprag bearing. It was a PITA to repair and rebuild. I haven't put it in another model yet though. I'm not put off the idea, but I think heat is something to consider with sprag style starters.

I do like what you doing with the bendix style idea.

Brian, I've not yet got round to implementing the bendix, it's a really easy job though, MVVS, King engine and others have done the same thing.

I prefer the disconnect the bendix offers, heard too many horror stories about the one way rollers jamming...

I'll report back, although Ian T-W has already had great success.

Ell.

Hi all,

finally got my starter mounted and running, I'm very pleased with the result. Currently (sic) running two 4s packs in parallel for the starter.

Ell.

Elliot ,pleased your starter works so well , the units I would recommend are the Italian Fiem units, these have a built in gearbox and bendix drive
I use a 250 watt unit for my King 190cc twin petrol on my two thirds scale Scheibe SF33 motor glider using a 3s 3200 ma Lipo battery
I have a couple more 400 watt units , one on my JPX 425 cc in my two thirds scale WW1 Hanriot biplane and the other in a three quarter scale 1911
Deperdussin monoplane ,342cc Weslake , these engines have the advantage of decompressors which allow the engine to initially to start on one cylinder and the open decompressor automatically closes , both use 60C 4s , 4500 Lipo,s ,the difficulty hand starting these two engines is the reduction drives with their un even ratio , for each turn of the prop, the compression point moves plus one swing of the prop turns over the engine almost twice.
Not a fan of the one way /torrington bearing , difficult to keep them lubricated .
Best regards Ian Turney-White

Elliot , I know its a glider site ! , but talking about self starters couldn't resist enclosing photo's of my self starter equipped Hanriot Regards Ian Turney-White

Oops , something went wrong !

Thanks Ian, that's all really useful data!

I'm using an italian bendix starter (very possibly fiem) off a scooter (which makes me smile (an old hobby)).

I ditched one battery so she starts really well off a 4s 4ah - I will experiment with 3s too. It's surprising just what a difference the prop makes, she seemed to struggle on the bench turning over, but clearly the momentum of the prop really helps with it's flywheel effect.

Just need to build a model for it now!

All the best, Ell.