REK OB Lower Units

[rek]

Just wanted to see if there would be an interest in my lower unit made out of a different composite material. My material supplier found some stuff in Denmark that would work for me. It is 23% lighter than what I am using now and the stiffness and strength go up dramatically. Here is the rub. The material will run me $24lb as opposed to $4lb I pay now and I have to buy 44lb bag to get it. This would mean for the performance lower unit it would be $41.95 and any other molded parts $9.75. These parts would have a molded mark to denote the difference in parts.

I would still make the parts I have now, I just need to know if the market is there to warrant the out lay for material.

Also if you posted to this at Rumrunner then do not reply here also.

Best regards,

Richard Konnen

 

[Kevin Whitehead]

Would this change in material help to lessen the chance of stripping out the holes with screws?

If it will, I think the change (and bump up of cost) would be a good idea. The market is going to grow for these lower units.

 

[Flyguy55]

I have 2 of your units now , I'll order a couple units .

Dick Roberts

 

[AlanN]

I think the stronger unit would be more desired. Not that I have had any problems with your product.

 

[rek]

Kevin,

What part did you have a problem with stripping out?

Richard

 

[LarryConrad]

Kevin,What part did you have a problem with stripping out?

Richard

The one I have I had to put nuts on the engine mount bolts because the threads wouldn't hold.

Larry

 

[Mark Leyde]

What do these units look like?

Mark

 

[rek]

Larry,

Can you give a picture so I can tell what part you have that is a problem?

Richard

 

[rek]

Alan,

Glade you have had no problem. The reason for this material question is that I am always trying to make them better for the racers. I know there will be a compliant to this comment. I have been building this lower unit for over 3 years and I am just now building and FE TS2. In doing so I have found a few areas that I want to change. Originally this was for nitro and to see if it could be done. Since I am putting my efforts into the FE. Also here is a company I sent a CAD file to that will laser cut a full length radio box for the TS2. To make it a new product for me would of made it to expensive, so I left it open to anyone who wants to buy them direct. http://www.rumrunnerracing.com/feforums/sh...ead.php?t=25966

I modified some existing plans for a full length radio box in the TS2. I got the part , rough assembled it with CA in 30 mins. You can get a full set laser cut from :

Laser Cut USA

612 SW Biltmore St.

Port Saint Lucie,FL 34983

1-772-528-4727

[email protected]

Best regards,

Richard

 

[dave roach]

Richard

Is this lower unit the same as the Irwin lower unit or a copy.

 

[rek]

Dave,

The lower unit Jim was selling was my lower unit, I just put his name on it. He was supposed to come out with an entire engine so I gave him OEM and put his name on it for him. He never came out with an engine so I pulled the OEM. As a result he got mad at me and I was stuck with him owing me for 50 lower units. Since the ones I ran for him, I have changed material and they are stiffer than before. Now I have come across another material from Europe that is much stronger and stiffer, not to mention lighter. The down side is the material is 6 times the price what I am currently using.

Best regards,

Richard

 

[Mark Leyde]

Dave,The lower unit Jim was selling was my lower unit, I just put his name on it. He was supposed to come out with an entire engine so I gave him OEM and put his name on it for him. He never came out with an engine so I pulled the OEM. As a result he got mad at me and I was stuck with him owing me for 50 lower units. Since the ones I ran for him, I have changed material and they are stiffer than before. Now I have come across another from Europe that is much stronger and stiffer, not to mention lighter. The down side is the material is 6 times the price what I am currently using.

Best regards,

Richard

So what would the final cost os these units be using the new material? If I remember right the the current price for one on FFE is around $90.

Mark

 

[Kevin Whitehead]

Kevin,What part did you have a problem with stripping out?

Richard

The lag screws going up into the motor plate, attaching the lower leg.

One of the four is partially stripped. I don't torque the screw in that corner at all. If I cranked hard at all on that corner the hole would completely strip out. I think that having to disassemble the leg several times has brought the problem on. Assemble it and leave it alone and it is fine.

 

[moparbarn]

i'm running 2 of your lowers with nitro. one rek, and one irwin (still says rek in small letters). no problems so far, but i use nylok nuts, bolts & flat washers to attach the powerhead on mine. the only thing that i have noticed is, upon reaching speeds approaching 50 mph, that the boat seems to hit a wall, so to speak. doesn't want to go faster, will go faster with a stock(k& B) lower. changing the steering to solid rods helped (was using cable/pull-pull). i suspect a flutter or high speed vibration, trimming the skeg SLIGHTLY, both in length & width helped, was able to go back to cable setup; & gain speed. would the new material being stiffer help, in your opinion?

 

[rek]

Kevin,

If the screws are 1/2" sheet metal philips screws, you can go to a longer screw to take advantage of the full thickness.

If you like to take apart your lower unit a lot, I can make a motor plate with Heli-coils for 4-40 SHCS for $14.95.

Richard

 

[TRUCKPULL]

Richard

Can you post a picture and some specs of the FE leg with motor mount.

Larry

 

[rek]

Well lets see if I can give you guys an idea of the difference in the material. Currently the material I am using is a hydrous material and takes on water from humidity. This makes the material tough but also adds some flex to it. The new material takes on very little water, which makes it stiffer. The current material has a Flexural Modulus of 1,000,000 and specific gravity 1.49. The new material has a Flexural Modulus of 1,700,000 and a specific gravity of 1.15. So new material is stiffer and lighter. This added strength should allow the skeg to be sculpted with a better airfoil, this would have to be done by the user. Unless I have a whole lot of time with nothing to do, then I would probably modify that part of the mold.

Best regards,

Richard

 

[rek]

Larry, Here is a picture.

Richard

 

[LarryConrad]

Larry,Can you give a picture so I can tell what part you have that is a problem?

Richard

Richard,

I don't know how to post a picture on IW. Mine is one of the units with Jim Irwins name on it. The threads wouldn't hold where the motor bolts to the top plate so as Robin stated in his post I use nylon lock nuts and bolts to secure the motor.

Larry Conrad

 

[moparbarn]

larry, is your power fe or nitro ? fe can mount differently than nitro motors. maybe why there's some confusion about what stripped out on yours. i never tried sheet metal screws, just figured the vibration of nitro motors would cause issues. fe's MUCH smoother, would work there ok, imo.