Check out our unique in-flight starter motor for the MVVS 26cc on a custom built Senior Telemaster.

The system is lightweight and robust. Works from a cold start. Works again and again... it is great for extreme long duration flights and vibration free (i.e., no image blur) video or stills while the engine is off. Also, for all those people struggling with gyro drift, you can get a good gyro fix when the engine is off as well.

 

Cheers from the MotMen UAV team, Newcastle, Australia.

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Comment by Paul Mather on July 10, 2011 at 9:06pm
I like your work, but I wonder why you went with an internal combustion engine instead of electrc? It seems like electric has so much less vibration issues.
Comment by Robert Dielenberg on July 10, 2011 at 9:31pm
We anticipate flying our small UAV (wingspan 2.1m) for 3+ hours with a full payload package point-to-point (i.e., not thermalling). Have you heard of an electric motor doing that? Now imagine putting our starter motor system on a high performance wing (say a glide ratio of 40:1). Imagine how long we will be able to keep that in the air. The idea is to push the duration a small UAV can effectively stay in the air (doing work like image mapping, surveillance, radio-relay etc).
Comment by Helldesk on July 10, 2011 at 9:52pm
Very cool! What battery do you use for the alternator?
Comment by Robert Dielenberg on July 10, 2011 at 9:55pm
LiPo
Comment by Alexey Burlakov on July 10, 2011 at 10:46pm

Nice work. Care to share any details on how you did that? 

 

Have you considered using the starter as electric generator for on-board equipment or battery charging? That would extend the flight time even more.

Comment by Robert Dielenberg on July 10, 2011 at 11:13pm
If you visit our website www.motmen.com -> products -> UAV page, you'll see that we have already deployed a generator system (but on the front prop shaft). Now that the starter motor is there, we will put our second version generator on the back of the crank case (with a specially engineered adapter). We're engineering that as we speak. We would rather not release precise details on how we engineered the starter motor, suffice to say it is extremely simple (but hard to make simple). Development costs were significant! The next step will be to work out a plan for cloning it if someone wants one, make it affordable I mean.
Comment by Alexey Burlakov on July 11, 2011 at 12:31am
So you will have separate generator and starter?
Comment by Robert Dielenberg on July 11, 2011 at 12:36am
Yeah. We thought about combining them, but it quickly became unfeasible. The advantage of keeping them separated is less wear and tear, easier to interchange for maintenance. The downside is you carry more mass. However, you can compensate for that by slightly increasing the size of the UAV airframe, from around 2.3 m which it is currently now (I said 2.1m before but I remeasured it) - to say about 3.2 m. Eventually we'll move to a 4.1m wingspan anyway.
Comment by Alexey Burlakov on July 11, 2011 at 12:52am

Cool. I've been thinking about high-aspect ratio UAV of about 4m myself, that's why I'm so curious about this generator/starter stuff.

 

Good luck to you guys, I'll keep watching.

 

PS: How much does current UAV weight? What flying weight is planned for 4m version? 

Comment by MarcS on July 11, 2011 at 4:04am

Did you do calculations if powering up and gliding down is more efficient then having a motor running non-stop on low power? Despite the fact that with survey you want to keep constant altitude the overall energy to keep an aircraft in the air is just the drag over time, which should be the same for both flying methods.

So a Telemaster is probably not the best reference for drag... Had to fly one as UAV in high winds, even takeoff gets a stunt :-)

Try to look for proven designs on that task: Aerosonde and Scaneagle: Low drag, highly efficient motors -> Flying times 20h+

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