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Author
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Topic: how to make propellor less effective?
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charmstar
Pilot
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posted 03-01- 07:43 PM
   
The plane I'm working on currently flies way too fast. I know I can slow it down by either modifying the airfoils to produce enough drag, or just putting a gigantic cylindrical airfoil in, but that doesn't give the effect I want. Sure, it keeps the plane from going fast, but it _should_ be able to go fast in a steep dive. What I really want to do is make the engine/propellor less effective, without decreasing the HP, RPM that I know the engine had, or modifying the number of blades or prop radius. What's the best way to do this? charm IP: Logged |
Sv
Pilot
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posted 03-01- 07:51 PM
There is a great tutorial on this at the OPPs site. A word doc. It is key.------------------
-Sv =FC=
WWI in SDOE!
IP: Logged |
Raider
Pilot
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posted 03-02- 09:16 AM
charmstar, I have found the best way to adjust top speed with little effect to climb/dive rate is to decrease the prop radius. This is more effective than prop max pitch or horsepower. RPM does have a strong effect here too but not as much as Prop radius. I had to increase climb rate by reducing phyLBS. I set the horsepower, RPM and max pitch to spec. Then adjust prop radius until I get the correct top speed. With the wings set to spec and using the best airfoil I could I then adjust phyLBS until I get the correct climbrate. This was a challenge with the DVII because it had a top speed of 124 mph and an unbelievably good climb rate for a WW I plane of 3000 ft in just 1.5 minutes. BTW Thanks for your help with control surfaces and stuff. Raider {GS} [This message has been edited by Raider (edited 03-02-2000).] IP: Logged |
Burkey
Pilot
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posted 03-02- 03:31 PM
What plane would that be then?  IP: Logged |
Tailslide
Pilot
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posted 03-02- 04:40 PM
By phyLBS do you mean the weight of the plane or the prop? If you reduce the weight of the plane below the real thing it'll turn too good. TS
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Whirlwind
Pilot
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posted 03-02- 09:30 PM
You could also add a engGearRatio to the engine as well - decreases RPM, boosts torque.IP: Logged |
Raider
Pilot
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posted 03-03- 01:44 AM
TS, It is the phyLBS of the plane. I had to reduce the amount of aileron movement to slow down the roll.I could not for the life of me get that thing to climb 3000ft in 1.5 minutes with a top speed of 124 mph, 185 HP, at 1400 RPM and a weight of 1500 lbs. Would you mind looking at the DVII and see if you could help us here? Thanks Raider {GS} IP: Logged |
Tailslide
Pilot
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posted 03-03- 01:50 AM
I ran into the same thing with getting the Spit1a to get enough climb and top speed with such a tiny engine. It's possible but it takes lots of trial and error with the propeller. You need to experiment with different blade section widths. Just for kicks why not try copying some of the 5.3 propeller declarations for the fw190 or 109 onto your plane? They're the best climbing planes in SDOE. TS IP: Logged |
Raider
Pilot
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posted 03-03- 01:55 AM
Thanks TS, I will try that.Raider {GS} IP: Logged |
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