Flywheel drive with starter on pulley end?

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Mike von S.

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Folks,
I am building a Flitzer Goblin and am interested in installing a flywheel drive VW (probably 2180). Because the standard starter ring won't fit without a radical reshaping of the bullet-nose cowling (which would kill the charm of the aircraft), I hoping to install the starter on the pulley end. In the HBA Conversations section I asked Pops about this. He said it should be possible, but he is not aware of anyone having done it.
Have any of you?
Thanks
 

Vigilant1

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Folks,
I am building a Flitzer Goblin and am interested in installing a flywheel drive VW (probably 2180). Because the standard starter ring won't fit without a radical reshaping of the bullet-nose cowling (which would kill the charm of the aircraft), I hoping to install the starter on the pulley end. In the HBA Conversations section I asked Pops about this. He said it should be possible, but he is not aware of anyone having done it.
Have any of you?
Thanks
Just for context, why are you seeking to go with this configuration? Mounting the prop to the pulley end allows the starter ring to be at the back (where you want it) and it allows use of the large Force One hub and bearing that is very desirable in a stroker Type 1 direct drive engine.

Google Image Result for http://www.aeroconversions.com/images/products/AeroVee_2.1_6855_275.jpg

But, to answer your question, I haven't seen a starter ring mounted to the pulley end.
 
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Mike von S.

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Vigilant1,
There are practical reasons and a philosophical one.
The Goblin is a very compact aircraft and was designed originally for an 1835 VW with no starter. In this configuration, only 6 1/4" are needed from case to firewall. In the slightly larger Z-21 Flitzer, at least one builder used the AeroVee 2180 with the Diehl accessory case. He moved his firewall aft by 2 1/2", leaving 5 3/4" to the firewall, just enough to fit the starter. This required a smaller fuel tank, to which he added an extension. My build is already too advanced to think about moving the firewall, so an accessory plate like the Diehl won't fit. Yet, I have no interest in hand-propping.
Philosophically, what Bob Hoover wrote about the flywheel end being the proper place to mount the prop, makes good sense to me. The recent (July2020) thread here on HBA (to which you responded) about a spate of crankshaft failures involving the Force One hub, which was supposed by many to immune to this fate, underscores, for me, anyway, the appeal of configuring the VW the other way 'round.
 

dwalker

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If you must go with the flywheel drive take a page from the Corvair folks. I myself am considering a flywheel drive setup for my Dragonfly, but have not made a firm decision. Most of that is because the option to use the Deihl starter/alternator setup vs a lightweight alternative setup, and how that might change packaging.

Here is how mark handled the balancer end starter setup on the Corvair.


 

Mike von S.

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Am I looking at this right: Langford had in mind a starter connected to the pulley end with V belts?
 

Pops

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Buy the after market center of the pulley. Bolt the starter ring gear flex plate to it, Mount the starter on the case pad where the generator stand bolts on.

When the VW was first used to power aircraft, mounting the prop on the flywheel end was standard.
 

Hot Wings

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If your case has the universal mount bolt pads you might be able to fabricate a starter mount there as well.

No reason you can't start a VW from the pulley end. After all that was one of the original starting options and has been done on industrial versions.
 

dwalker

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The type 4 he was using a flywheel on the flywheel end and a prop extension to allow for the sleek nose
 
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rv7charlie

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Just to be sure, you do realize that the starter will have to be re-configured to turn the other way, right?
 

Mike von S.

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Yes, but in my blissful ignorance I'm assuming that's a simple matter. Polarity or something?
Most a/c starters turn the opposite way, don't they?
 

Daleandee

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One concern voiced by William Wynne for those wanting to do this with a Corvair engine is the stress of putting all the starting loads on the retaining bolt and the small keyway cut into crank for the pulley (harmonic balancer on the Corvair).

Another concern is the twisting the crank will experience with loads on both ends. These must be acceptable as it's done now with most VW conversions with the prop on the pulley end and the ring gear on the drive end. If I were doing this it would make more sense to use the drive end for both the starter & the prop if at all possible.
 

rv7charlie

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Yes, but in my blissful ignorance I'm assuming that's a simple matter. Polarity or something?
Most a/c starters turn the opposite way, don't they?
Might be on a particular starter model, but you'd need to disassemble it to find out. In 'stock' form, one end of the winding is grounded to the case of the starter and the other comes out to the terminal. Might be a trivial change to reverse it; might not.
 

Mike von S.

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Daleandee - interesting points. Thanks. We are still hoping to fit the starter up front, with some modification to the bullet nose. I've asked GPAS for dimensions or scalable drawings of their flywheel setup, but haven't received anything in response, so far. In the meantime, a fellow Goblin builder in Canada (who ordered what might turn out to be the last Verner 5V for his own ship) is a wiz with technical things, and has taken an image from the GPAS website of the engine and roughly superimposed it on digitized Goblin plans. Conclusion: it might work as is, with some modification of the cowl (and ballast in the back, as I am well smaller than a "standard" pilot).
 

Mike von S.

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Might be on a particular starter model, but you'd need to disassemble it to find out. In 'stock' form, one end of the winding is grounded to the case of the starter and the other comes out to the terminal. Might be a trivial change to reverse it; might not.
OK, thanks.
 

STDJantar2

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The flywheel used by the GPAS is the Chevy Flexplate 168 pin attached to a cut down VW 4 or 8 pin flywheel.
 
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