clemsparks

Hi all,

In your experience, what's the best overall prop for my 21.5 oz Davey Systems Fokker Eindecker (sp?) and cox TD .049. My experience showed that the old, product 3 blade props actually worked well (better than some two blade props I had) back several years ago when it last flew. I've inferred that this might not be a popular concensus, though. I've lightened the plane to the current weight (21 1/2 oz).

If I've left out any info, please let me know.

Thanks,
Clem

DICKEYBIRD

I like the 6x3 & 5x3 Cox black nylon props on Tee Dees. They have good thrust yet less load and heating problems than some of the other ones. Your Eindecker would probably like the 6x3. A 6x2 APC or 6x3 Master Airscrew works pretty well at low airspeeds as well if you can't get a 6x3 black.

combatpigg

My Feedback: (3)

HI CLEM! I was taught that a 2 blade prop is more efficient than a 3 blade, and when working with these tiny engines there isn't that much efficiency that is acceptable to lose. This scenario of yours sounds like a good time to shift into LOW GEAR[prop pitch], and follow DICKEYBIRDs' advice. APC has a 5.5-3, or you can experiment with a 6-3 and remove some diameter. The 6-2 works OK, just make sure you have a healthy engine that can deliver the needed RPM to lug that much weight around.

BMatthews

The weight of the model does not enter into the equation. If you want power you choose the prop that allows the engine to produce the most thrust while operating at it's peak POWER RPM and not neccessarily just scream for the sake of screaming.

The Cox black 2 blade are good but in my experience the TeeDee really sings with the grey 6x3 or 6x4's. But it's hard to find the Cox grey competition props these days so I tend to use APC props. Try the 6x3 or 6x2 for a good pull in the climbs. Those 3 blad props had very low pitch which may just let the TeeDee wind up while producing less thrust.

For the Eindercker with it's large front cowl you may be suffering from cowl interference. I know standard theory says the cowl is not supposed to matter but if it's very close to the back edge of the prop and quite blunt it may be causing interference. Your solution may be to position the engine forward by using a 3/8 inch shim of plywood behind the mount so the prop is out in clean air.

21.5 oz IS on the heavy'ish side for 1/2A but it's not that bad. If the props don't help then try moving the engine forward and retrim the balance. Oh, and be sure your balance is in the 30 to 35% range. If it's too far foward the wing can't perform like it should. The only problem with this would be if the model uses the scale size horizontal stab.

clemsparks

I don't have a cowl on it, but the propeller barely protrudes past the projection of the fuse (if that makes sense).

I don't really totally remember the scenario of my past flights (it's been over 5 years ago) but for whatever reason, in it's heavier form, the plane just wouldn't hardly gain altitude with the other props. I have a feeling I'm getting facts mixed up though. I'll try to get a hold of a few props and do some experimenting...AFTER I teach myself how to fly agian.

Thanks for the help folks,

Clem

PS. I picked up a cool vintage tool tray that will make a really neat field box, I think. It's painted steel!