.12 hammerhead (project speed)

[_laxmasta2039]

oh whoops... :

well, ummm....actually...ummm i knew that and i was just joking..... : : ;D

Joe

 

[MikeP]

If anybody is interested I found the Sirio motors at a pretty good price 139 and 149 for the outlaw. Some other good motor prices as well.

http://www.brucknerhobbies.com/Trinity%20S...rio%20Rossi.htm

-MikeP

 

[TomMoorehouse]

wow that is a good price!

 

[Hammerhead]

Which do you guys think is better, a floating mount that has two seperate pieces(no under plate), floating mount with under plate, or a solid mount. Keep in mind this is for a .12. On the prototype .12 hammerhead, I'm using a floating mount with no under plate. Seems to work fine. Some think that you can get more torque to the screw with a solid mount. Some say that the under plate prevents your engines case from warping.

Opinions please.

Hammer

 

[MikeP]

I am going to build mine with the motor back plate screwed to the bulkhead like the pylon racing airplanes do it.

With this setup there will be less weight without a mount and no need for doubling the sides of the tub for motor mounting. There should be no case stress, I don't know if you get more power to the screw.

I always mount my servos with the vibration mounting kits that come with them and pad the Rx and batteries with or without a floating motor mount.

Now, can anybody give me 1 good reason to use a floating motor mount?

-MikeP

 

[Hammerhead]

I use them by habit, but I really don't know what they are good for other than dampering vibration.

Hammer

 

[E]

I always mount the engine rigidly. I think of the engine mount as a free-bulkhead. Instead of making the tub stronger to hold the engine in, the engine mount actually stengthens the tub.

I see the rigid engine mount as a free structural member in the hull. I've been using wooden engine mounts with good results. Normally I use a brass 4-40 insert. On my new hull I did not use the 4-40 inserts and instead made the threaded area 1/2 deep. If push comes to shove you can even drill through the engine mount down to the bottom of the tub and install a nylon-lock 4-40 nut.

I use pull-starts so the pylon engine mount method will not work for me. I know Tom uses this method on his Fire Fighter .12 w/ success.

 

[Don Templeton]

I like the solid mount for the structural strength. I take a 1/4" aluminum plate and mill 1/8"off except for a 1/4" wide strip on each side under the engine mounts so I can drill and tap. I do think Mike's back plate mount sounds pretty neat but I would think you would need a very strong, hard bulkhead. I would think there would be a lot of stress on the bulkhead when you use the electric starter. :-

 

[TomMoorehouse]

octura 3-30 mount works for me .21's and .12's

you can make it pretty darn light and polish it to a nice sine!

 

[Don Templeton]

Hey Tom,

Is that mount 3" wide and does it mount through the sides?

 

[Ron Olson]

Don, yes it does. I use one in my .12 mono. You can really lighten it also if you want, I removed a lot of weight off mine.

 

[Don Templeton]

Ron,

The first rigger I ever built was an Octura .67 Wingding. It came with probably a 4 or 5" alum. 1 pc mount that looked kind of like an I-beam on it's side and bent down in the center with raised mounts in the middle. The boat used alum. wing shaped I-beams that bolted through the sides and the motor mount holes and then onto the inside of the sponsons. Cool looking boat for the time. Does the 3-30 mount look like what I described.

Don

 

[Hammerhead]

Okay! You've got me on the strength aspect, but how about increasing torque to the prop? How about solid shaft drives vs. flex shafts? I have heard a lot about that, too. It seems like in our club, most of the younger guys use flex shafts, and the older guys use solid shafts. I always thought that this was just one of those, "You can't teach an old dog new tricks" things. Let's here it. Is there more to it than that?

Hammer

 

[Don Templeton]

Well Hammer,

I'm an old dog and I'm learning the flex shaft. The solid shaft works great if you have a long enough boat and set up correctly with ball bearings. I used to love to watch that prop spin like mad in a light wind when the motor was out of it. However the drawback is you can't adjust it unless you hang a U-joint in front of the strut. I think all of this adds up to additional weight you don't need especially on a .12. We always built a well in the bottom of the tub to lower the engine and flywheel as much as possible. Also you really don't need to use a bolt on strut at all if you go without a U-joint. What I know you wouldn't like about it is it intrudes on the radio box area! ;D

 

[TomMoorehouse]

stock and modified octura 3-30

 

[E]

Tom, how much does the before and after 3-30 weigh?

... and who does the aftermentioned modifications?

Eric Perez

 

[Ron Olson]

Eric, once you get your holes drilled in your motor mount for the motor, it will give you an idea of how much you can remove. do it any way you can, Dremel, drill, bench grinder, etc. I couldn't tell you the weight off hand, it depends on how much you remove.

Don, it sounds like the same, just smaller.

I don't havea lot of experience with hard shafts, only 2 boats, a Kyosho Hydro-Jet (?) and the CEN Racing Grey Thunder in my basement now.

 

[TomMoorehouse]

i just had a friend of mine do it with a milling machine. i have no idea the weight but it is pretty light afterwards

 

[Don Templeton]

Yep, that just like what came with the old Wingding. Very nice mount except you'r limited to 3" inside hull width.

 

[MikeP]

I found a back plate mount today for a .12 I think I will give it a try.

www.ad.kengarff.com/mikep/backplate2.jpg

-MikeP