Extreme Flight Owners Thread

[gyro]

How do y'all like it?

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Damn, we've got twins


Sorry about your plane Robert

 

[dth7]

Damn, we've got twins
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Sorry about your plane Robert

Maybe those twins can get a "group" discount on a nose job? Don't like seeing "lost" Lasers.

 

[YellowJacketsRC]

I have been trying hard to master the rolling loop. It's just about the only 3D maneuver that still escapes me. I had a break through today and then made the mistake of switching to high rates.....

 

[Ohio AV8TOR]

I use the prop power calculator Pe Rievers (sp?) made. I find it very helpful in doing prop comparisons.

Is this in chart form or a number calculator. Yes a link would be great. I know PE is gone so maybe no links so would you email it?

 

[Buick Mackane]

I have been trying hard to master the rolling loop. It's just about the only 3D maneuver that still escapes me. I had a break through today and then made the mistake of switching to high rates.....

Sorry for your loss dude. That's a bummer

 

[Ohio AV8TOR]

I use the prop power calculator Pe Rievers (sp?) made. I find it very helpful in doing prop comparisons.
.

I think I found this calc, is this it?

 

[Enterprise]

That is very similar. The one I have is from PE's website and I think it is newer as it has a lot more pages and props in it. PM me your e-mail address and I will send it to you.

 

[3dNater]

When I plug it all into the prop calculator, the DLE-35RA on the ES pipe is more Horsepower than the 40 twin. It just achieves it at a higher RPM with a smaller prop. The DA-35 will probably be in the same category. The advantages of the twin are:

1) more torque in the low end (not overall torque) for spool up
2) smoother and lower idle
3) less vibration
4) ability to swing a larger prop. 21x8 versus a 20x7. 7k RPM versus 9.5k

it is somewhat analagous to using a lower KV wind in a electric motor.

For my particular flying style twins works better. High energy junkies will like the singles more as you can rev them up. I have tried a 20x10 on my twin, and yes it hauls the mail, but there is a lot of torque from that high pitch that hurts you in hover and harrier.

Are you saying you spin a DLE 35 up to 9500 rpms?

 

[Ohio AV8TOR]

PM me your e-mail address and I will send it to you.

Sent

 

[Aeroplayin]

Pe and I conversed a lot about this when I was building the PropEngine. The pK was always the issue, and the main point of our discussions. In his very last post on another forum, he suggested two formulas to me because he always had issues with prop load constants, and these formulas dealt with prop power absorption. I worked on adding a moving variable to my PropEngine because of his suggestion, and I found (as he probably did) that there was no load 'constant' after all... it's a variable.

You can use the PropEngine for gas props too as long as you know the material of the prop... beechwood or wood laminate, composite, carbon fiber, etc. It works well as it is now, and the output is accurate, especially if you know the RPMs because you just move the Kv up or down until you match the RPM display with your measured number. The newer version, which I will deploy in maybe a month, will be easier to use with gas engines because I now have a way -- thanks to Pe's suggestion and ability to pinpoint the issue -- to calculate pK. I also have a way to calculate Kv efficiency because of size and RPM load (rotational mass and angular momentum) so using this for gas prop comparisons will be even easier.

The Chinese developed a thrust chart for gas engines and props, and if you use this to test the PropEngine, you will find that the average of the Thrust value and the Static Thrust value will line up perfectly with this for at least all the props I compared (a lot). The difference is probably the different atmospheric conditions. You can find this chart by going to this page on the Falcon site and clicking on the Technical Info menu option at the top of the page.

The new PropEngine will also have a way to calculate or input air density using elevation and temperature, or by using this calculator to make the output even more accurate, and give us a way to compare the reported output from around the world. So far, we've tested data from Florida, to Seattle, to Anchorage, to Scotland, to Australia, and have confirmed finding up to a 27x10 from beech and laminated Xoar, wood Vess, wood Falcon, CF Mejzlik, and now CF Falcons, and will move on to the Vess stealth and Xoar CF this year (maybe). It's a free tool, and always will be.