Author Topic: A small favor .... How do you mount your motor? (Read 2858 times)

Rudy Taube · « **on:** October 31, 2009, 02:35:15 AM »

A small favor:

How many of you are mounting your motors to a rearward firewall (rear motor mounting with most of the motor forward and the shaft forward)? ... and are you having any problems with this setup? ... TIA

How many of you are mounting your motors to a foreward firewall with the motor "non turning" part mounted facing forward with the main rotating part facing aft. ? .... and do you feel this is the best method of mounting? and why? ..... TIA

Any photos of your motor mounting system would be greatly appreciated. You can post them here or email them to my email address here on SH. ..... Bob pays us SN writers a lot more if we provide photos. In fact he more than doubles our pay if we do!

Regards,

Mike Anderson · « **Reply #1 on:** October 31, 2009, 07:18:29 AM »

Rudy:

There is a fairly extensive discussion of this subject, from last spring here:

http://stunthanger.com/smf/index.php?topic=11517.0

I don't have any photos currently, to illustrate things, but there have been a couple posted that I can think of that address your question (though I put a drawing in the above thread) - Find Crist's photos of the motor mount he fabricated for his "570 in. profile" and also search for Dean's photos of the rear bearing and holder that were fabricated for Bob Hunt.

bob branch · « **Reply #2 on:** October 31, 2009, 08:01:35 AM »

Rudy

There are pics in the T-Rex build thread here on the forum.

Rick Sawicki and I have discussed nose mounting vs radial mounting outrunners a number of times. He is still running an axi 2826/12 after 4 years on a Tudor II and a year or 2 in an rc bird before that. All radial mounted with no issues. I have up to 3 years on several in cl and rc with no issues. Rick has quite a number of electric CL as well as RC (he has only flown electric in both for at least 4 years... rc much longer) and relates he has never had an issue as a result of radial mounting.

bob branch

Alan Hahn · « **Reply #3 on:** October 31, 2009, 08:28:00 AM »

I mount mine to the back firewall. I haven't had an issue with the motors I run---Scorpion 3020, which if you note, are 20mm magnets (and iron shell), compared to the AXI 2826 which are 26mm magnets and longer iron shell.

The issue comes down to whether you think our square maneuvers put a lot of stress on the aluminum support structure (the parts where the bearings are mounted). This could possibly allow the rotating shell make contact with the stator arms---there isn't a lot of clearance there. Some of longer motors--like a Scorpion 3032 and I think the Orbit-Plettenburg have an extra ring bearing just to support the end of the iron shell--just for this purpose. Also one worries about the bearings themselves.

Here is a question for people using the extra bearing support (like Crist and the one Bob Hunt shows in the latest MA). When I do a square maneuver, I hear a real motor "grunt". Is there less of a "grunt" with the extra support?? I am not sure what the noise is due to--bearing noise during the extra stress of the maneuvers, or maybe extra current the ESC pushes through the motor to account for the extra load (I don't seem to see any noticeable current spikes on my data recorder so I am guessing it isn't this).

Mark Scarborough · « **Reply #4 on:** October 31, 2009, 10:04:53 PM »

Alan, are you sure that isnt noise from the prop? I know on my E P-40, ( AXI 28-26-12) IIRC when I was using the 12X6E APC, I could really hear a pronounced noise on the squares. When I went to the 12x6 XOAR Wood prop, which is much stiffer, I no longer heard the noise as clearly, it was greatly muted. Engine load or prop load, my guess was prop load since it also varied in intensity with the RPM I was running

Alan Hahn · « **Reply #5 on:** October 31, 2009, 10:39:56 PM »

Quote from: Mark Scarborough on October 31, 2009, 10:04:53 PM

Alan, are you sure that isnt noise from the prop? I know on my E P-40, ( AXI 28-26-12) IIRC when I was using the 12X6E APC, I could really hear a pronounced noise on the squares. When I went to the 12x6 XOAR Wood prop, which is much stiffer, I no longer heard the noise as clearly, it was greatly muted. Engine load or prop load, my guess was prop load since it also varied in intensity with the RPM I was running

Mark,
I have no clue really to the cause---except I hear it in sharp corners

Rudy Taube · « **Reply #6 on:** October 31, 2009, 11:25:47 PM »

Hi Mike:

Thanks for the heads up, I'm aware of that fine thread. I was hoping for more data and photos from others, and/or more current data from those on that informative thread after another season of flying. :-)

Hi Bob:

Thanks, that is just the type of info I was looking for. As much as I think the forward firewall mount makes sense, my ERC experience shows me that the rear mount system also works well, just like yours and Rick's experience. If you have any close up photos of your ECL motor mounting system, please send them to my email address. If you get a chance, please ask Rick if he has any close up photos of some of his ECL motor installations. ... TIA :-)

Hi Alan and Mark:

Alan, I get the same sound in the squares (that is, on the rare occasion when I make my corners look square

). I allways attributed it to the thin E-APC props flexing and acting like a crude musical instrument. I get the same sounds in some of my violent ERC 3D maneuvers with 15 x 7 and 18 x 8 E-APC props.

Thanks Mark for verifying the above with your comparison and use of the much stiffer wood prop. BTW: I like the XOAR props on my larger ERC planes, how do you like yours on your ECL plane compared to the E-APC?

Looking forward to more:

Please share your experiences and photos with us. I am sure there are many people who are standing on the sidelines that are seriously thinking of joining us in using E power. One of the hurdles to conversion, is how to mount these "weird" motors that don't even come with normal mounting lugs on them! And ways to mount all that other weird "E" stuff too!

Thanks for the great info so far. ..... Photos form those not yet posted would be appreciated, they will be a big help for all, newcomers and old timers alike.

Regards,

walterbro · « **Reply #7 on:** November 01, 2009, 09:17:44 AM »

Hi Rudy - I have mounted my Axi 2826-10 by rear bulkhead since 2005.
I hear noises in outside squares with 12x6Ep props. Before I used Gov.control
I used 11x6 CAM props and there was no noise in squares. This was with much
higher RPMs than my current 8900rpm in GOV. mode. In my two twins I use rear
mounting with no noise in corners with 9x6 and 9.8 x6.3 APC Props and GOV mode.
I am curious to hear/see if fwd mounting like Plett orbit produces corner noises with stiff props like Paul Walker uses.

Sincerely, Walt Brownell

Mark Scarborough · « **Reply #8 on:** November 01, 2009, 11:54:42 AM »

Hving heard Pauls planes fly,
They make noise in the squares, but I really think in that case, its the air molecules rushing to get in the right place out of respect for the master!

Rudy,
I really like the XOAR, I feel it has much better bit on both the uplines and downlines. I regretably have lost most of this season due to a vast number of personal issues that have arrisen so my E plane is sitting dusty, as are most of my glow planes. Next year is the coming out year though.
Since CAD design doesnt cost much, I have however been developing a new Stunter for specifically E power. Not sure its going to get built. I actually have two in the works. One is a built up version of my Gee Bee Profile, but full on with stringers and fabric covering, should be ultra light. The other goes to the opposite extreme, its a full on profile for E power, 620 inches of wing, and some rather kinky ideas that I have worked out for getting the battery on the center of mass. REad that as a shoulder wing with Anhedryl,,, snicker,, oh, and in profile it looks like an F-16

Rudy Taube · « **Reply #9 on:** November 01, 2009, 01:22:42 PM »

Quote from: walterbro on November 01, 2009, 09:17:44 AM

Hi Rudy - I have mounted my Axi 2826-10 by rear bulkhead since 2005.
I hear noises in outside squares with 12x6Ep props. Before I used Gov.control
I used 11x6 CAM props and there was no noise in squares. This was with much
higher RPMs than my current 8900rpm in GOV. mode. In my two twins I use rear
mounting with no noise in corners with 9x6 and 9.8 x6.3 APC Props and GOV mode.
I am curious to hear/see if fwd mounting like Plett orbit produces corner noises with stiff props like Paul Walker uses.

Sincerely, Walt Brownell

Hi Walt,

Thank you for your report, it is always nice to receive input from one of the pioneers of E-Stunt. Your comments are very good news for all those who want to use this easy (rear mount) method to convert their wet systems to E power. It seems from your experience, and others, that this mounting system works very well for E-Stunt.

RE: Paul's system. I don't think his forward mount has anything to do with the lower amount of noise increase in his very SQUARE squares. Here are two reasons I believe this is true: 1. I think it is due to his very stiff CF prop. This beautifully crafted prop looks like a WWII fighters prop, with very wide stiff tips. It is thin, but very stiff, unlike the very flexable E-APC prop at the tip. 2. My Aluminum profile mount on my E P-40 allows me to mount my motor from the rear or from the front. When I changed positions the sound did not change.

It will be interesting to see if anyone has any further info. on this. When we get up to 12", and now 14" props, it sure is a very big gyroscope out there trying to prevent our plane from turning. I'm not surprised when they howl a little in protest!

BTW: for anyone reading this that does not fly E-Stunt yet, we are only talking a small change in sound. It does not get louder in the corners, just a different sound. I don't want anyone to think that the excellent, inexpensive E-APC 12 x 6 props that most of us use are loud, they are very quiet. But Paul's CF paddle blade prop sure does look very COOL!

Thanks again for your help Walt.

Alan Hahn · « **Reply #10 on:** November 01, 2009, 01:43:01 PM »

Sorry,
Didn't mean to hijack the original mounting question with my question about the corner "grunt" sound. Anyway it sounds (pun not intended but left in anyway

) that it isn't anything to do with the motor shaft flexing or bearings "groaning", which is what I was mainly concerned about.

John Cralley · « **Reply #11 on:** November 01, 2009, 07:23:47 PM »

Rudy,

For what it is worth (which probably is not much), I have three electric powered Ringmasters. All of them have the out runners mounted at the rear (stationary) portion of the motor. I have had no problems with this type of mount so far and I have crashed two of them (into turf) without any problems in regards to the motors. Well yes, I did break the collet type prop adapter off of one of my Scorpion motors but the shaft did not bend and I have had no bearing problems. So I will just knock on wood and keep using this type of mount for future profile models.

John

Rudy Taube · « **Reply #12 on:** November 01, 2009, 08:45:51 PM »

Hi John,

Thank you, that is a very sano MM. Is it an X mount screwed to the fuselage, then another X mount bolted to the motor, then sandwiched together? Or did you use a wooden X glued to the fuselage 1st? Your setup looks like a smart, clean way to do a mount in a profile.

I'm glad to hear that your rear mount is problem free. That helps confirm what others are saying too. .... Thanks for the photos.

Sorry to hear about your mishaps, we all have been there.

It is good to hear that our E motors are tough.

Regards,

John Cralley · « **Reply #13 on:** November 03, 2009, 08:24:17 PM »

Rudy,

That particular Ringmaster was purposely built as an electric. The black X mount is two 1/8" aircraft plywood pieces epoxied together to get a 1/4" mount. This in turn is attached to a piece of 1/2" maple "motor" mount placed vertically between the doublers (1/32" ply in this case). Before mounting the maple piece it was drilled and two blind nuts were installed so the plywood X mount could be attached with two 4-40 machine screws. I am now using nylon machine screws as an attempt to kind of make a "break away" mount for the motor. So far those nylon screws have NOT been put to the test --- and I hope they never are tested!!!! The photo below will give you an idea of how I set up the mount. The vertical maple fits in the notches and then the doublers are added.

John

Rudy Taube · « **Reply #14 on:** November 04, 2009, 01:34:29 AM »

John, You are a modeler's modeler!

That is a perfect profile mounting system. KIS, light, strong, inexpensive, and it looks cool too!

Thanks for the great photos. ......... Gee, a whole 1.4 oz for a fuselage, what's wrong, you couldn't build a light one?

Regards,

bob branch · « **Reply #15 on:** November 04, 2009, 09:39:10 AM »

This is the profile mount system I use. Can't claim it as original. I just copied Rick Sawicki's structure and adhered it with a structural adhesive I have used for years. Structure is 1/4 in ply epoxied to the fuse (in this case a Brodak P-40 arc) with a mix of epoxy and West system #403 microfibers adhesive filler. We use this blend in 100% scale boat building to bond hull sheeting together without underlying structural members. It makes an extremely strong thixotropic (does not slump or sag) mixture. Like any filler in epoxy it will increase the reaction surface and cause the mix to kick much quicker so use slower epoxy and be prepared. Don't mis a lot. btw, it does not sand well. It really hard when its done. But it is very strong and vibration resistant. The fillet increases bonding surface area.

I use blind nuts where I cannot get to a nylock nut. I build the mount with zero offset and then use an RC engine offset wedge to create any engine offset I want. The black wedge between the motor's radial mount and the plywood is a 2 degree wedge. They are available in a number of sizes. I primarily use one,two, and three degree wedges. This is not the spinner for the plane, just used it for positioning purposes.

bob branch

John Cralley · « **Reply #16 on:** November 07, 2009, 11:05:23 AM »

Rudy,

Thanks for the kind comments. I was trying to keep the weight down to compensate for that dang heavy battery. The fuselage is made from three layers of balsa adhered together with contact cement. A 1/4" layer with vertical grain between two 1/8" longitudinal grain sheets and then scroll sawed to remove as much as is reasonably possible.

So far so good.

John

Paul Walker · « **Reply #17 on:** November 11, 2009, 01:27:24 PM »

Here is a question for people using the extra bearing support (like Crist and the one Bob Hunt shows in the latest MA). When I do a square maneuver, I hear a real motor "grunt". Is there less of a "grunt" with the extra support?? I am not sure what the noise is due to--bearing noise during the extra stress of the maneuvers, or maybe extra current the ESC pushes through the motor to account for the extra load (I don't seem to see any noticeable current spikes on my data recorder so I am guessing it isn't this).
[/quote]

I flew Crist's plane at the Nats. It makes a LOT of noise in the outside corners. It had the extra mount on it.

On my planes, I am sure the noise IS coming from the prop. I can change nothing but the prop, same engine speed, same lap times, but different prop, and change the noise. In fact, the first flights on the 62 ounce Impact made no noise in the corners. This with the same props that made noise on the 70 ounce planes flying at a very similar speed.

I am convinced that all this noise is prop. And, it can be mitigated by pitch, rpm. and flight speed. You just have to experiment.

Me, I go by what makes the plane fly best, and then worry about the noise.

Paul W

Crist Rigotti · « **Reply #18 on:** November 11, 2009, 01:42:39 PM »

What Paul says about my set up at the NATS is correct. I noticed that it did make more noise on outsides. I changed props to the 12 x 4.5P (Adamisin) prop and the entire setup got a lot quieter. It still is "more" noisy on the outsides though. Not sure why and I have given it some thought, but never any real serious thoughts. At first I thought it might be bearing noise but never really persued it. I suppose I could take off the rear bearing support and fly it and see what happens.

Alan Hahn · « **Reply #19 on:** November 11, 2009, 03:04:59 PM »

Quote from: Crist Rigotti on November 11, 2009, 01:42:39 PM

What Paul says about my set up at the NATS is correct. I noticed that it did make more noise on outsides. I changed props to the 12 x 4.5P (Adamisin) prop and the entire setup got a lot quieter. It still is "more" noisy on the outsides though. Not sure why and I have given it some thought, but never any real serious thoughts. At first I thought it might be bearing noise but never really persued it. I suppose I could take off the rear bearing support and fly it and see what happens.

I wonder if your outside turns might be tighter than the inside.

I got a flight in at lunch today on my Nobler--I am still trying to get the darn airspeed and altimeter sensors to behave, but that is another story.

I noticed that even in the inside round loop (so not even squares) that I could hear more noise than the outside loops--and that my insides were tighter than the outsides by far (yes I know that I should fix that!).

John Hammonds · « **Reply #20 on:** November 11, 2009, 04:03:28 PM »

Hi Rudy,
I'll post mine for what it's worth. I just went out and bought a strip of aluminium angle from a local DIY store. I saw off the length I want and shape as necessary. A strip of hardwood inset into the fuselage at the point where it's attached to the fuselage and bolt through that. Weight is minimal, not the prettiest solution but it's solid as a rock in use.

TTFN
John.

John Witt · « **Reply #21 on:** November 11, 2009, 06:04:22 PM »

There's a picture of the motor mount in my Vector 40 posted in "List your Setup". It's not a profile, but some may be interested. It's pretty light and quite solid. It's very similar to the mount in my Panther.

John

John Witt · « **Reply #22 on:** November 11, 2009, 08:05:12 PM »

Second try at getting this to post. If one of the pictures is too big, the whole thing dumps.

The motor mounts are made from the wet engine mounts, drilled and tapped 6-32. Threads are then soaked in thin CA. 3/16 balsa doublers are added to space the hardwood correctly.

The wing LE was cut back and the cuts stiffened with 1/32 ply, to allow battery length (2650mAh Zippy).

John

Rudy Taube · « **Reply #23 on:** November 11, 2009, 11:28:21 PM »

John H.,

That is one beautiful mount. Not only KIS, but it is light, strong, REAL easy to make (looks like something even I could do ;-), inexpensive, and it looks like it is adjustable too. :-)

I assume that there is another duplicate on the other side.

By elongating the holes, as seen in your photo, this allows you to adjust vertical thrust, and offset, very clever.

After looking at it a few times, it dawned on me that your mount might work on a full fuselage plane conversion, by rotating it 90 degrees, and using 1/2 of the already installed beam mounts (after removing the forward portion of the hard wood beam mounts).

Your mount gives us yet another excellent solution for those wanting to go ECL. Thanks for the cool photo.

Regards,

Rudy Taube · « **Reply #24 on:** November 11, 2009, 11:39:57 PM »

John W.,

Where were you when I was doing mine? I used a bulkhead, but I like your method better.

It looks strong but lets the air flow to the ESC/battery much better than my bulkhead does.

I'm glad you mentioned it, I was looking for ALL types of mounts, not just profiles. So your addition is great to have. I hope we see more full fuselage mounts.

Like some of the others, Your mount looks light, strong, inexpensive, easy and KIS. It fits right into the very good design work found in many CL planes.

Thanks for the perfect photos.

Regards,

John Hammonds · « **Reply #25 on:** November 12, 2009, 02:45:02 AM »

Hi Rudy,
Yes as you say there is another similar mount on the other side. I was planning on using it as you suggest in a Claus Maikis Commodore I'm currently converting but looking at John W's solution I think that is so neat I'll probably go with his idea instead.

TTFN
John

John Sunderland · « **Reply #26 on:** November 12, 2009, 10:29:25 AM »

Quote from: John Witt on November 11, 2009, 08:05:12 PM

Second try at getting this to post. If one of the pictures is too big, the whole thing dumps.

The motor mounts are made from the wet engine mounts, drilled and tapped 6-32. Threads are then soaked in thin CA. 3/16 balsa doublers are added to space the hardwood correctly.

The wing LE was cut back and the cuts stiffened with 1/32 ply, to allow battery length (2650mAh Zippy).

John

Thanks for the info John! Looks like an easy set up that does as Rudy says, allowing airflow to the back for better cooling

Dennis Toth · « **Reply #27 on:** November 12, 2009, 02:04:09 PM »

Guys,

Seems that most of those that have posted to this thread are using rear mounts. I have used the front mount consisting of 3/16 plywood that fits between the original maple motor mounts and has a half round upper section that sits on the maple mounts (kinda looks like a "T" with a half round top) and bolts to them with brass "L" clips. Cooling holes match the cooling on the AXI 2826/10 motor. I have used this approach in the Test ship that was full fuse and it works quit well. I know others are using front mounts and would like to hear some of the details.

Best, DennisT

Author Topic: A small favor .... How do you mount your motor? (Read 2858 times)

Alan Hahn

Alan Hahn

Alan Hahn

Alan Hahn