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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Motorman on September 10, 2017, 01:53:21 PM
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Someone told me glow engines still have an advantage on a windy day.
If that's the only advantage I prefer to avoid the slime. S?P
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Someone told me glow engines still have an advantage on a windy day.
Fail to see any logic in that statement
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Someone told me glow engines still have an advantage on a windy day.
Probably told by a guy who wants to sell his engines! :)
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Probably told by a guy who wants to sell his engines! :)
I am not sure where the OP got the information, but I have told people that on several occasions. I think the generally heavy line tension of electrics is probably a liability in heavy, smooth air, and a perfectly-running piped engine seems to respond better than the Igor feedback system to help keep the coner speeds under control. I noted this effect at the 2015 NATS Top 20 day and 2015 Golden State where, in both cases there was about 20 mph+- but very smooth air. Both times, I had essentially no difficulty getting through with a competitive pattern, and never had any real doubt or concern about it. Particularly at the NATs, several highly-competent electric fliers came down rubbing their hands and having had to expend great effort to keep the airplane under full control in the maneuvers. Not that this really means all that much, but in both cases I came out on top for the day - highest two-score total at the NATs for Top 20 day (and David and his PA75 had the single highest flight {but got inexplicably killed on the other one to the point it was possible he would miss the flyoff}) and won the Golden State.
There are several problems with my theory, of course, the primary being that you have to have your system working nearly *perfectly* and that's not always possible - compared to electric which at least will repeat its performance regardless of any outside influences. I think my percentage of hitting that is much higher than average but it's not 100%.
Note also that the flip side is also true - while a perfect IC system might work slightly better than a electric in this small subset of conditions, I think electric works, generally, *much* better in dead air and hot conditions. There, the sometimes brutal line tension can be a bonus and again you aren't trying to fight the prop and the engine at the same time*.
In fact, I am so sure that this is the case that I am working on a new setup just for the case of dead air:
https://stunthanger.com/smf/engine-set-up-tips/alternate-ro-jett-61-setup/
So far, so good on that one, and I think that all is required to switch to the good wind setup is change the prop and the launch RPM - not the pipe length, venturi, or fuel. In fact the needle is pretty darn close, if I switch to the baseline prop, leave the needle, the RPM pops back up to within 100 rpm of the right speed for that prop. It's a little touchy on the needle with the big prop, suggesting the pipe is a hair too short, but moving that would make switching back and forth much more difficult.
Note that this illustrates the other issue that will eventually drive everyone to electric - nearly all the adjustments are electronically-settable and infinitely repeatable, the only possible exception being the accelerometer tilt or skew- which is still a lot easier to do than change the pipe length or venturi.
Brett
*Same as a 4-stroke, actually, in that regard, but the 4-stroke is a huge liability and a handful in heavy air, far worse than an electric due to the nearly complete lack of accommodation.
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If I was to "play stunt" the only serious option would be lectric.
I'm collecting stuff for a scale project and it makes huge sense to use electric in it. Fortunately, I mostly fly seed these days so ic is my choice.
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Mine doesn't not demonstrate "heavy" line tension.
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thinking your dbl negative gave em the slip! LL~
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I mostly fly seed these days so ic is my choice.
Ken went to seed long ago.
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Someone told me glow engines still have an advantage on a windy day.
Well, the results from the last few F2B World Championships doesn't seems to agree tho.
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In my experience it also depends on the size of the model. Obviously I am specializing in small models. I am a real fan of electric where appropriate, but it isn't there yet for true half-a size planes. (Assembling an electric Flite Streak as we speak, and next up is a Prowler).
The best small electric I have flown so far is a Baby Pathfinder, but it needed the equivalent of .09 power as an electric. The performance was good, but it would have been spectacular with a Tee Dee .049 or AME Norvel .061 on pressure.
But it is getting there! Give it a few more years and IC is toast. (I doubt it will ever match a Tee Dee .010 on 40% Nitro, but maybe someday).
About 20 years ago I predicted that IC powered ducted fans would be replaced by electric power and they all laughed. Who has the last laugh now?
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Well, the results from the last few F2B World Championships doesn't seems to agree tho.
Which of those were held in the conditions described above (i.e. pretty strong but extremely smooth) conditions? That's where I think perfectly-working IC (i.e. piped 2-stroke) has an small advantage, and it's probably at a disadvantage in light/dead air or turbulent conditions. I think you will find that it is the latter for the recent (perhaps most) WC.
On of the advantages I see with electric is that in almost all case, even with airplanes that are otherwise at least somewhat less-than-ideal in terms of trim, it almost never has that feeling of "falling into" corners. The corners always seem to require/have a positive feel, and the feel is closer to the same at different points on the circle. Frequently you will get substantially varying feel/feedback in the corners with IC engines, even from one corner to the next.
Brett
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Brett, could you please expand on your "relatively heavy line tension" regarding electrics comment? What differences between EP and IC result in different line tensions, given similar models in proper trim. What prevents an EP model from being trimmed with line tensions similar to an IC model?
Or for that matter, what are the differences in the two power systems that prevent two similar planes being trimmed to have the same feel throughout the pattern?
Thank you,
Bruce