Kevin,
I am a full time woodworker/custom furniture builder. I work with wood in my shop (self emplyed, 3 man shop) for 50 hours/week. I dont want to start making props as a side business believe me! :stupid: HAHA!

I do metalworking and mechanical stuff as a hobby/pastime and when I saw that photo of the prop copying machine I had to build one. Thats how we got "here".... All for fun!

But if they are good, I would probably be obliged to make a few!

Now its time to go to work! (building furniture that is, not more props...)

Andrew

I got the wood versions of the APC 12.25 x 3.75 props from Andrew today. I can't belive it, but the mail showed up at 6:30 PM
Here is a pic for you guys to drool over.
Kevin

Kevin,
I am just leaving for the day, be back tonight... I hope to hear something about my props, even if all the blades broke off (hope not!)

Even if you didnt get to fly them, if you ran them let me know....

Talk to you later,
Andrew

I had a 20mph wind flip my Knife with a 12.25x3.75 prop and ruin the tips. I'm going to try the shortening concept to make it a 12 x3.75.

Andrew - winds were too high here today to fly. We are having gusts of over 30MPH, so I didn't even try to fly, though I did set-up in the backyard and run them. This is my results for just taching them in the backyard and weighing them. My daughter happen to bring home from school a precision scale so I used it.
Manuf. Size WT. Tach
APC 12.25 x 3.75 42 grams 14.3K
AJC #1 20.76 g 13.8K
AJC #2 24.8 g 14.1K
AJC #3 26.6 g 13.4K
Y&O 12 x 4 19.73 g 14.7K

It is strange that #2 did better than #1 since I had to do the most work on it to balance it. Usually I have found that it is the other way around. Hopefully the weather will be better tomorrow. By the way, the Brodak Y&O 12 x 4 prop broke in my hand at the hub when I went to remove it from the motor. Sure glad that it didn't happen in the air! It would have torn the plane apart before I could get on the ground, or stopped the engine. Needless to say, the throttle response on yours was significantly better than the APC. That I expected with the weight difference. The Y&O had the best throttle response, though it also flexes with RPM and is the lightest, but after it broke in my hand just loosening the prop nut, I don't think that I'll order any more. Too dangerous!
I let you know how they perform in the air first chance that I get.
Kevin

OK sounds good. Glad mine didnt break in your hand!

I think the #2 prop (the one that is just about 1/32 thicker than the apc) is better than #1 as it is much stiffer yet not too thick. Not too much down in RPM from the APC, at 200 rpm.

Almost 1/2 the weight, I hope it performs where it matters, in the air!

Andrew

Andrew - I would think that ordinarily, #1 will perform better, but like you said, the proof is in the air. Weather permitting, I'll try them tomorrow.
Kevin

I ran the props Andrew sent to me today. We had a high of the mid 40's, cold wave for us, though there was hardly any wind, so I went out. I'd have to say that they were a great success. I tried #2 first since it produced the max. RPM on ground test. Response was great, pulling power was better than the APC 12.25 x 3.75. I have no idea why Andrew's version pulled better, but I had to drop my dual rates by 20% across the board to realize comparable performance. The APC must flex more than I realized, where Andrew's did not. I allowed a friend to try #3 while I ran #1. I firmly believe that #1 had the best response rate, though it should since it was the lightest. I may have been my imagination, but I believe that it was better than #2, though barely. #3 was better in throttle response than the APC, though should be. #3 didn't perform as well as #2 & #1, though expected.
I want to thank Andrew for giving me the opportunity to test these props. They worked fantastic!
Kevin

Ajcohlic
That is one nice machine. What did you use for bearings on the arm that holds the router? Thanks.
art43

The bearings are "linear ball bushings", they are cylindrical bearings that are designed to ride on a shaft back and forth, and also rotate. Very neat. Should be available at any larger bering dealer.

Just ask for "linear bearings" and tell them they are to ride up and down a cylindrical shaft.

ANdrew

The most common ones that I have used is Thompson or THK. I used these allot in my CNC Machine Design days. They both make excellent linear bearings. There are other manufacturers of these bearings, though if you tell them that you are looking for a compariable linear bearing to a Thompson or THK, they will know what you are talking about. Any motion control outfit carries them, WW Grainger & McMaster Carr as well (though more expensive at these 2 places).
Hope that this offers some additional assistance.
Kevin

Thanks guys, I might try to make one my self this winter. art43

Art,
Go to the tips and techniques forum, do a search on propeller making or prop making and you will find more usefull info.

Andrew

Here is a link to a bunch of linear bearings. Go to the Linear Pillow Block Assemblies for a good starting point. http://www.wmberg.com/catalog/catres...EAR%20BEARINGS

Andrew, could you do a rough sketch of your set up with dimensions?

Thanks,

Dale

Yes I could. However, in order to be readable I cannot post here. If anyone is interested I can email them personally. It may take me a few days or more to get a chance to do it, as I am super busy with work (christmas rush is on, orders to be finished up!) and have to take 10 or 15 minutes to jot down the info.

When I have the sketch ready I'll post it here and you guys can email me!

Andrew

Thanks for the replys.I will do the search on props, also would be interested in A drawing of your prop cutter.
art43

I've been running the Zinger 16x5 cut down to 15 dia. and modified according to 3Dreaming on my Ecstasy w/ ST90, Mac header and tune pipe. I was flying a APC 15x4W originally at 11,400 RPM. I ran the modified Zinger last weekend and it ran at 10,600 RPM. I swept the angle back some more to be 1" from the tip, radiused it, then thinned the blades. This prop ran in the high 11s (I think - not quite enough light for my tach yesterday, but obviously higher RPM than the APC). It flew great. Still not the pulling power of the APC, though great throttle response!
Kevin

I just wanted to bring this back to the top of the stack. I have referred to this thread an serveral occassions for people and thought that it would help to get it back on top of the stack.
Kevin

Kevin,
Did you finish and fly the 14-5 wood apc copies yet?

I have been flying my 12.25-3.75 wood props on my fun fly plane this summer so far (been flying for about 3 weeks now) and I really like them. Broke two allready though

AJC

No -AJC I've been busy with other personal issues. Did you say to spray them with urethane after I finish sand and balance them? I do desperately need to get to work on them. Have you started on that Wacky Bee III yet?
Thanks Again!
Kevin

Kevin,
I have three fun fly planes flying right now (and about 12 or 14 other planes) so I probably wont get to build the wacky bee untill I smash up one of the others... probably later on this summer the way I fly

As for finishing, I like to use Varathane in the spray can, the fast drying black label, solvent based, high gloss - 3 coats. Gives a rock hard glossy finish that looks great and stands up well (I use it when I refinish wood golf clubs also)

Andrew

What brand do you use? I realize that wood working is your speciality (I'm still looking for mine <LOL>)
I flew my Wacky-Bee III today in 10 - 20 MPH winds. I was hovering it in a knifed edge - SWEEEEET! I had a ball with it!
Thanks for the Info AC!
Kevin

Varathane is the brand, its made by Flecto - I believe it is made in the USA and should be available anywhere.

Any poly will do, but I like Varathane since it dries fast and comes in a spraycan.

AJC

I just read this whole thread. Being many months later, let me ask: How are the Bodak props working, and are they still available? Thanks

The Brodak props did not work very good on the 2 strokes, but they worked almost OK on my Saito .72. Tom