WattFlyer RC Electric Flight Forums - Discuss radio control eflight - View Single Post - Reduce speed envelope of Great Planes RV4?
Old 12-17-2010, 09:48 PM
  #10  
Dereck
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Join Date: Oct 2005
Posts: 1,071
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Welcome aboard Syd
FIrst off, if you're used to larger IC powered models, you may be fascinated, nay - amazed - by how lightly a small electric model can be built.

First off - visit the master's shopfront. His name is Pat Tritle. Look up any of his designs - they all weigh about half of what mere mortals can built to.

Start with the firewall - in your old life, you were anchoring an IC lump that vibrated, weighed a lot and sent shivers down the airframe every time the fuel in the head went 'BANG!' Now you have a little alloy cylinder spinning around back of your prop, propelled magically around with no vibration whatsoever.

2lb is a little hefty for your model, plus your Rimfire 10 could be a little excessive.

Possible cures, given that taking weight out the airframe now could be tricky. A 1" smaller prop would be the cheapest approach, as you're flying on relatively trivial amounts of available power now. Next up the cost-cutting after trying that is going to 2S.

A balancing act here would be a 2S LiPo - go for the same mA rating you have now, or a little less dependant on what your pack can handle in current draw - and a smaller diameter prop with steeper pitch. You'll be juggling pitch speed (higher) for RPM (lower) and hopefully getting a little freeby with lower weight.

Your next step is a smaller motor. Perhaps not a bad idea, as you certainly seem to have an excess of grunt up front right now. That would require more spending and perhaps some Very Hard Sums though Let's try and get your 10 to play with a spherical object first.

And please - put the servos back inside. The last aircraft that looked good with its controls on the outside was DeHavilland's Tiger Moth. Just because the IMAC kiddies put their servos on the outside - to show off how much they spent, one suspects - doesn't mean that the rest of us should demonstrate such appalling taste

Don't expect too much. Regretably, we fly small models in standard sized air and those effectively bigger molecules don't do such a good job of holding up smaller flying machines.

Keep us posted. You've done a good looking little model there

Dereck
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