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seamaster engine mount from plans?

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Old 11-08-2011, 11:42 PM
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flybyjohn
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Default seamaster engine mount from plans?

Is or has anyone used the engine mount in the configuration that it is shown on the seamaster 40 plans? I will try and explain it real quick. The 4 bolts on the back of the engine are removed but keep the rear cover in place. Then a 1/16" aluminum plate that is drilled for the bolt pattern on the rear of the engine is placed against the rear engine cover. The bolts go back in and are tightened down. This aluminum plate is slightly larger than the rear of the engine so that holes can be drilled through it and it can be flush mounted on a flat plate of wood, which would be the engine pod mount.

This is how it is shown in the plans and I know that you can just bolt a nylon engine mount to the engine pod but this looks a bit lighter. I was just wondering if it has been done much and if the 4 bolts in the back of the engine are strong enough to hold onto the engine. Any comment or suggestions anyone?
Thanks.

Another question I will add to this one is about the water rudder. I am cutting out wood right now to build this seamaster and was wondering if I can just add a sub fin and extend the air rudder a little further down and use it for the rudder instead of adding the aluminum one the plans called for. I have seen it on some similar planes to the seamaster but not on a seamaster yet.
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Old 11-09-2011, 05:07 AM
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Default RE: seamaster engine mount from plans?

Don't know about the mount, but you can do that with the water rudder
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Old 11-09-2011, 05:21 AM
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Default RE: seamaster engine mount from plans?

I have a Sea Dancer and that is the way it is done on that plane. Works great. Very good control in the H20
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Old 11-09-2011, 09:28 AM
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Default RE: seamaster engine mount from plans?

My rudder is made of wood and is held in position by using a nylok(sp???) nut with enough tightness to hold in place. but loose enough to swing up if it should strike something in the water or beaching. Nice to have that swing away feature. Engine mount idea is interesting, but seems like alot of work, used nylon mount on mine, not much of a weight penalty and it is located near the CG.
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Old 11-09-2011, 10:58 AM
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Default RE: seamaster engine mount from plans?

I was thinking about the swing action on the original rudder but then thought if the plane had a subfin, anything that would strike the rudder would just slide up the subfin like a ramp. So any weeds would not get stuck.

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Old 11-09-2011, 11:47 AM
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Default RE: seamaster engine mount from plans?

I vote subfin. that's how they did in on the Lanier Mariner and the newer seamaster clone, the Neptune and Neptune II. I like it better with the sub fin, as my old seamaster's fold away one was always folding away. If I tightened it, it would stay for a couple of landings, then the balsa would give a little, and loosen up again. I supose you could glue a brass tube and rub plates to keep it tight, or add springs, but it's so much easier to just add the sub fin and extend the rudder down. The only reason you might not want it is for grass take offs. I sometimes drag the tail a little if I am doing STOL drills and on grass, it might hang up. In the water, it's kind of cool to come in on a low slow pass and drag the tail for 5-10 ft.
I have never hung mine on anything in the water. I expect it would do better than an overtightened brass rudder hitting something. At least there is a subfin to kick the tail up before something hits the rudder.

On the motor, that's almost how the electrics are mounted, but it seems like a lot of bother for glow given how many mounts are available. I would just buld light, and not sweat it too much.
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Old 11-09-2011, 11:53 AM
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Default RE: seamaster engine mount from plans?

I am trying to attach a picture of the plans that show the engine setup. I think I will go ahead and put the subfin and extended rudder on while I am building from scratch it should be quite easy.
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Old 11-09-2011, 04:32 PM
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Default RE: seamaster engine mount from plans?

Nelson used to market a mount for OS engines. You'd probably benefit from slightly longer mounting screws to compensate for the thickness of the mount.

www.ebay.com/itm/NELSON-40-Q-500-RACING-ENGINE-W-RADIAL-MOUNT-NICE-/290599704612

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Old 11-11-2011, 06:04 AM
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Default RE: seamaster engine mount from plans?

Find the engine mount design interesting, I'm one who likes to stick with what I know works, curious to hear what others think of this particular type of mounting system, pros and cons. I do like the throttle servo up in the engine pod, my Seamaster is built from the kit and uses the flex rod for throttle, it has worked well for me but, would use servo in future plane.
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Old 11-11-2011, 08:50 AM
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Default RE: seamaster engine mount from plans?

I just looked at mine, which is an untested $50 swap meet item with a ST .51 and a warped wing.  It has no subfin at all, and the servo in the fuse with a regular mount.  I think a subfin is not really needed in the Seamaster at least.  It is only needed for taxiing in the wind and once it is up to speed it doesn't matter.  It would be in the water until the speed is up. The best subfins I saw were long brass L shaped affairs that were loosely fit to bounce up when hitting obstructions.  I would use 1/8" alum. for the motor mount and maybe longish countersunk screws. I like that idea but would check to make sure the motor isn't loose every flight, and use the blue loctite if it is a problem. It is really no harder to mount a motor this way than a plastic one.  8 holes to mark out and drill, and four of them can be through drilled easier than with a plastic mount.
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Old 11-17-2011, 08:06 AM
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Default RE: seamaster engine mount from plans?

When I converted my seamaster to electric, I decided to go with the lightest mount I could design, that would also carry some of the strength down to the thicker plywood portion of the pylon. I settled on two pieces of angle aluminum that sandwitched the pylon and provided the 4 bolt points for the motor. On my Lanier mariner, I went with a shorter bracket, as the pylon was strong enough all the way to the end. I think as long as you locktighted them, maybe glued with epoxy, the angle to wood joint would be plenty strong. The long standoffs might be too twisty for a glow motor, but they should be shorter than I used, so they might work. Esp if the plan shows the motor mounted right to the firewall. I have always been more comfortable with metal than wood, so building the transition from vertical pylon to firewall out of wood blocks seemed like un-needed work. Don't know how you want to mount a tank, my seamaster just used two dowels pointing back from the firewall, but they could be attached to the pylon just as easily.
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