Morris Mustang scratch build (Full Version)

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yojoelay -> Morris Mustang scratch build (12/4/2007 8:42:32 AM)

After thinking about it for a while I've taken the first steps in scratching a Morris Mustang from some plans found on the net.

This is my second build after a long hiatus from that side of the hobby and my first scratch build. If past experience is a guide, progress will be slow. Suggestions are welcome. I am working with a limited tool set - hand saw, razor blade, no power tools except a drill. Glues will be aliphatic resin and 30 min epoxy - I like to put about 2 hours building time in and then leave things to sit.

The aim will be to build a no-fuss fun fly aerobatic plane. Power will either be from an OS 46AX, or a Saito 56 - open to suggestions on that one. Because I fly at a busy field I'll likely install landing gear - hand launching and retrieving when 4 or 5 other planes are in the air is a bit hairy. Flight gear will be a basic Hitec set up.

Balsa was purchased from Queensland Balsa here in Brisbane. The wood looks beautiful - better than anything I've ever seen in a kit - which is making it a joy to work with. Their packaging was a bit ordinary though and their was some minor damage upon arrival. I'm happy with the wood and the price so the damaged bits will be overlooked.

A local printer printed the plans out on A0 sized paper - the largest they had but not quite big enough to capture the scoop on the bottom of the fuselage. Printing wasn't cheap - over $20 when they were finished but the guy who did the job was an ace and real easy to deal with, and the paper is nice quality stuff. Since I'm not in this hobby to save money it wasn't a big concern. Will post their name soon - they were located in the West End on Boundary Rd for anyone in the local area.

So the first step is to kit-out the build. Looks fairly straight forward - ribs and some fuselage bits. Here are the ribs - love how fat they are! I decided to take the extra time and cut some lightening holes since the wood was so nice to work with and the ribs were so huge so they should stand up to it.

Time invested in the build so far - about 2.5 hours



yojoelay -> RE: Morris Mustang scratch build (12/4/2007 5:02:15 PM)

One more thing,

The plans were downloaded from:

http://www.willingtons.com/mymac/Plans_Download.htm

Scroll about half way down the page and find 'P51D Profile'

I also picked up a free demo copy of DeltaCad to look the plans over at:

www.deltacad.com

You can print it out on regular sheets with DeltaCad and tape them together but I had them printed professionally on a large sheet - personal choice really.

Please download a copy and jump in if you're interested in participating in an international build - beats the hell out of the old penpal thing, doesn't it?

All the best,

Joel



mmattockx -> RE: Morris Mustang scratch build (12/4/2007 5:55:40 PM)

Hey Joel,

That is a great site, lots of interesting plans to have a look at.

Thanks for the link,
Mark



somegeek -> RE: Morris Mustang scratch build (12/5/2007 2:13:01 AM)

quote:

ORIGINAL: yojoelay
www.deltacad.com

You can print it out on regular sheets with DeltaCad and tape them together but I had them printed professionally on a large sheet - personal choice really.


That's great! Thanks for sharing. Was able to print out Paul Swany's Taco .25 plans to scratch build a profile.

somegeek



batchelc -> RE: Morris Mustang scratch build (12/5/2007 2:44:06 AM)

Yo,

I'm also building a morris mustang (probably from the same plans). I'm a bit closer to flying but I've been working on and of for a year. I built this plane to get back into the hobby. Last year I built and flew 3 spads to get my flying skills up to par.

I streached the tail 2" and did not build the scoop.

Here's some pics:






yojoelay -> RE: Morris Mustang scratch build (12/6/2007 3:05:20 AM)

batchelc - that's the one. Looks like you're getting close.

Two questions:

1 - How did you build the wings? Can you pin down the ribs flat to the board and build the whole thing in one piece or do you need to support the ribs individually? The plans show a 'building board line' along the bottom of the rib and the bottom spar is positioned to lay flat on the board. Any input on the sequence used for assembling the wing would be appreciated.

2 - what are you doing for rudder and stab control linkages. The plans show a pull/pull set up - but I do have some spare pushrods lying around that would be nice to use up. Again, any suggestions welcome.

Haven't touched the ribs since they were cut out - might get back to it tonight for a while. Will tackle the fuse, rudder and stab until I figure out how to go forward with the wings.



batchelc -> RE: Morris Mustang scratch build (12/6/2007 11:38:55 AM)

1. I built the wings flat. If you look at the ribs I think the lower side ift of the spar is completely flat. Just pin them to the board and start gluing. I did use 1 strip of carbon fiber on each spar.

2. haven't really descided yet. Probably some carbon fiber push tubes with ball links on both sides. I may do a pull-pull set up depending on the cost. You really want a positive control linkage set up with no slop. But then again unless you go with digital servos, going through the extra effort may be a waste.

I did not fully sheet the fuse because I increased the thickness of the wood that I used for the fuse. It was what I had laying around. If I was to do it again I would sheet the fuse only because covering it would be easier. You can see some wrinkles in my covering job becasue of the open framework. If I had a chance to sand down the open frame more it may have come out better.

This should be a fun one to throw around the sky.

I'm painting mine as a "Blue Nose ****" - "Sweet n' Lovely". The real full scale "Sweet n' Lovely" lives about 2 hours from me and my friend's dad rebuilt the engine in that plane....

Chris



yojoelay -> RE: Morris Mustang scratch build (12/6/2007 7:07:26 PM)

Thanks batchelc, I'll build the wing flat. I'd thought about only sheeting part of the fuse as well, or redesigning the framework entirely with a carbon rob for a spine (similar the the Mojo 40?) but since no-fuss simiplicity is my overarching aim I'll follow the plans on this one.

My balsa stripper ran hot last night cutting the sticks for the rest of the build plus a few extras since it was set up. Did a garage clean up afterwards and decided against rebuilding an old Piper cub that crashed hard after an aileron servo failure. The wing had an old single servo set up with two plastic flexible Sullivan pushrods inside - the red straw with the yellow tube inside - so they should provide a positive, no slop set up.

Time invested so far in the build - estimate 3.0 hrs + garage cleaning and reclaiming parts from a donor plane.



yojoelay -> RE: Morris Mustang scratch build (12/8/2007 2:25:58 PM)

I had a spare building board that was just big enough to start the fuselage so away we went. Framed in the fuselage and the rudder - they are a one-piece affair - in just under 2 hours. Lots of sanding to try and get tight joins - still learning this but getting better each time.

I must have bumped my balsa stripper between cuts because the 3x 1/8th strips along the bottom of the fuselage were cut a bit narrow. I'll likely have to do a bit more light sanding than initially anticipated to get everything flush before putting the sides on.

Once the rest of the rudder is done the fuselage will wait until I get to the LHS to stock up on 1/8" lite ply, and the wings and stab can get underway.

Time invested - 5.0 hours.



FLYINMIKE-RCU -> RE: Morris Mustang scratch build (12/8/2007 8:02:25 PM)

I Had A Morris Mustang Several Years Ago That I Built From A Kit. One Of The Best Flying Profile Planes That I Ever Had. I Opted To Put Mechanical Retracts On Mine Just To Be Different And I Already Had Them. Flew A Lot Different With The Gear Retracted Than When It Was Down. Even Put A Scale Color Scheme On It. I Still Have The Plans And The Rib Punch-Outs On Hopes Of Enlarging It To About 80" Span One Of THese Days.
Good Luck With The Build.



yojoelay -> RE: Morris Mustang scratch build (12/11/2007 1:00:09 PM)

I've had 2 more sessions with the Mustang over the last few days.

The first session was to finish the motor mounts, frame in the remaining 'cowl' area, and place a few gussets around the fuselage. The second session began with fabricating the belly pan, then edge glueing a couple of sheets of balsa together, sanding them lightly, and placing the sanded fuselage frame on top of them. I used some large tiles that were lying around to weigh the whole thing down flat.

Unfortunately I realised that in my haste to glue the sides on I hadn't made it to the LHS to buy that lite ply for stiffening up the motor mounts and nose area. The glue had pretty much set so I'll assess the strength of the front end and figure out a strategy next session. Any suggestions are welcome - really the biggest issue I see is how to mount the motor without compressing that 1/16" balsa. At the moment I might carve away the balsa that is offending the motor mounts, and make some 'balsa plywood' using bits of 1/16th laminated together and substitute that for the lite ply nose doubler. Unfortunately I don't have pictures - I'll get some when I take it out from under the tiles.

I got the stab underway as well, pretty straight forward stick construction using 1/4" sq and 1/8 * 1/4 balsa. I decided to put some extra bracing into the thing - mostly because my joints aren't the best - so I'm confident that it will stay together and the weight gain was marginal at best.

Total time invested so far - about 9.0 hours



GuyP -> RE: Morris Mustang scratch build (12/11/2007 5:00:58 PM)

Hi

Nice build! watching with interest.

Can you not add 2mm ply over the top of what you have already done? Will be fine although you will have a slight line down the fuse where its 2mm thicker each side.



mmattockx -> RE: Morris Mustang scratch build (12/11/2007 6:05:25 PM)


quote:

ORIGINAL: GuyP

Can you not add 2mm ply over the top of what you have already done? Will be fine although you will have a slight line down the fuse where its 2mm thicker each side.


This would be my choice. The original Taco was sheeted with 1/16" ply this way and it worked fine for holding the nose together.

Mark



yojoelay -> RE: Morris Mustang scratch build (12/11/2007 8:11:58 PM)

My concern with putting ply over the balsa is that when the motor gets torqued down the balsa underneath will compress and the motor will come loose. Maybe I just cut away the balsa back to the hardwood motor rail to create just enough space for the motor, and then sheet the rest with ply? Any thoughts?

I see we're getting into metric here - which is actually how we measure most things in Australia. 2mm is around 3/32" isn't it? I watched your Hots build a few weeks ago with interest - any luck since the crash?

Thanks again.

Joel



mmattockx -> RE: Morris Mustang scratch build (12/11/2007 8:16:35 PM)

If you are worried about crushing the balsa, sheet one side with ply and inset some dowel pieces where the bolts go through and then sheet the other side.

Mark



GuyP -> RE: Morris Mustang scratch build (12/11/2007 11:36:14 PM)

Hi

To be honest I wouldnt worry. The balsa in between the hardwood and the ply will only act as I kind of spring washer if you like. As long as you bolt is tight as you normally would I'd not be concerned about it come loose, you will be surprised how strong it is. However Marks ideas a good one.

Yeah the Hots is covered as of today thanks, just need to get the canopy markings back on and I hope to fly over the weekend. The weather in the UK has been a load of crap over the last couple of weeks plus ive been busy with chores and getting ready for xmas.

Still got to decide which engines going on it. TT GP42 or Saito .62. I know which will be best but I may keep the Saito back for another project. hmmmmm decisions



yojoelay -> RE: Morris Mustang scratch build (12/12/2007 1:08:53 PM)

Right - here is the plan then. I'm going to cut back offending balsa from the motor mount, head to the LHS for some ply and then sheet the nose over top of the balsa and closely around the motor mount. I'm not convinced that crushing the balsa is the best route - I have a mental picture of exposed grain and absorbing oil of the motor, and of washers that come away looking like saucers from the compression treatment. The motor mounts are wide enough (3/4") to still gain plenty of support from the ply sheeting and the sheer strength of the balsa should help out.

The other side of the fuselage is now glued on and things seem nice and flat. It still needs to be cut out but that seems to be a fairly easy job. The ribs required a small doubler that spans between the spars - not sure what you'd call that piece - but they're attached now. The rest of the session was spent sorting out landing gear and radio locations before getting in to the wing.

I decided to delete the wing tips to simplify things. I read about someone doing this in a post from a few years back with little impact on the flight characteristics. Comments on this are welcome.

The entire flight pack looks like its going to fit in the wing quite nicely. My plan is to mount the servos on lite ply hatches and run the servo arms out through a grooves in the hatches. The two aileron servos will sit outboard in between rib #2 and rib #3, exiting the bottom of the wing. The receiver, rudder and stab servos will sit between rib #1 and rib #2 on the left hand side of the aircraft, exiting the top of the wing (I think - we'll see). The throttle servo and battery will sit on the right hand side of the aircraft, with the throttle servo exiting the top of the wing (again - we'll see).

The landing gear is carried over from a Phoenix Scanner. Ribs #2 and #3 will be reinforced with lite ply and two pieces of 3/8" hardwood run between them forming a groove and surface to fasten to for the gear. I have some tires from that ARF but they may be too small - will see.

No pictures as there wasn't really any visual progress.



nort -> RE: Morris Mustang scratch build (12/16/2007 10:59:20 AM)

Hi, this is my first post here. I still have my morris stang from 93. If I was to build one again, I would absolutely add more rudder surface by at least 1/3. Elevator is almost enough on max throws but could just as easily be enlarged as well. Plane still has mvvs 40 with mvvs pipe. It will run forever on 8oz. 10%. otherwise it is a cool profile. Follow plans if you must but Knife edge is hard to hold.



yojoelay -> RE: Morris Mustang scratch build (12/18/2007 1:04:20 PM)

Hi Nort,

THanks for the tip. I've already build the stab and rudder but I'm not really happy with the joins and I was thinking about re-doing them. I found a great little tip on cutting angles accurately that is making all the difference. Will provide a link next time.

Unfortunately I don't have any photos and have fallen behind a bit on keeping the post up (excuses, excuses) - I can't find my camera charger but it is around. The camera came on a recent work trip and the charger is ??? Anyways, we'll work something out.

In the meantime the plane has progressed somewhat (take my word for it). The fuselage is sheeted, the wing spars, ribs, rib caps, shear webs and trailing edge are in place and I'm just waiting to have a few moments while others aren't sleeping to cut out the bits and pieces for radio and landing gear mounts. Once the gear mounts are in the leading edge will get closed up and the sanding will begin.

The LHS came to the party with all the necessary parts except the carbon fiber - I arrived right on closing time and missed grabbing it, but it shouldn't be hard to return now that I'm on Christmas holidays. The ailerons haven't been built yet but if I'm going to get into increasing surfaces, well, everything might get a tweaking. Was their enough authority with the stock ailerons? I've never seen one of these planes fly.

One of the things I'm loving about this scratch build approach is that if you're not 100% happy with something it feels a lot easier to throw it out and begin again. I'm no longer limited (and I guess I shouldn't have been in the past) by the balsa supplied in the kit. I have a pile of great wood to work from, it wasn't all that expensive, and there is enough there to do another couple of planes - very liberating.

In the meantime, it is the peak of summer down here any the temp in my garage is well over 30 degrees - something like 100F? Doing a lot of sweating while building.

Will try and get some pictures soon.

Joel



yojoelay -> RE: Morris Mustang scratch build (1/7/2008 4:00:07 AM)

Sorry for the short hiatus but between visitors and trouble with a camera it all got a bit hard over the Christmas break. I did get a lot of building done though, and worked through a few problems as well.

First big step was landing gear. The plans show a retract arrangement or a belly landing arrangement. I decided to retrofit some gear from an old ARF by placing some plywood formers on ribs 2 and 3 (see pictures) then gluing two narrowly spaced rails between them. The rails lay flat against the leading edge sheeting, and provide a solid foundation for the landing gear screws to bite into (see pics again).
Due to space constraints and some poor planning I wound up having to remove the wing from the board and turn it around in order to install the landing gear and glue the leading edge on (see pictures). If anyone builds this model I suggest building the wing with the leading edge towards you if you have a smaller building area. Anyways, it all worked out. With the gear mounts installed I closed up the leading edge top and bottom by gluing the sheeting to the ribs.

I realised that in my haste to put the leading edge on I had selected 5mm balsa rather than 6.5mm. No worries, I pulled out some 2mm and laminated onto the 5mm, leaving a bit of extra sanding space - sorry, no pictures of that). Sanding went quickly - it's not a big wing really.

Anyways the wing built flat on the board and all up was pretty pleasant to do. It is very rigid and hopefully will handle some abuse as well. I still need to glue a carbon fiber strip on to the bottom spar where the left and right sides meet up but I'm saving that for an epoxy session sometime soon.

Next was the radio install. The aileron servos each sit on hatches that are mounted into bottom of the wing. The mounts are 3/8 hardwood with ply to reinforce to ribs. I was planning to do something similar with the throttle, stab and rudder servos but realised that with a bit of work I could lay the servos flat against the hatch and have the control rods exit the wing leading and trailing edges respectively. The extra effort seemed justified for a neater radio install, so after a bit of swearing and some reasonable luck it all fit together.

The last bit of building was the ailerons. Beacuse my aileron servos sit outboard between r2 and r3 a new attachment point was required for the control horn. An extra piece of 3/8 * 1/4 was glued in and should handle the load. I omitted the wing tips as well, so the tips of the ailerons had to be shortened so they didn't stick out. This was done during building as well.

Anyways, I've run out of time for uploading pictures but will try to get them up in the next 24 hours.

Joel



yojoelay -> RE: Morris Mustang scratch build (1/7/2008 6:11:58 AM)

OK - some pictures.

The rib doublers for the landing gear are the tear drop shaped pieces of ply, which were glued into place on the ribs between the spars and leading edge.

I also took on the suggestion to increase the surface area of the rudder. At first I planned to rebuild it but I decided to just run some 3/8" around the outside of it - which worked quite nicely and saved a bit of time.

I don't have pictures of the radio install but hope to in the near future. Have been called away on business for the week so hopefully I'll have something this weekend.

Joel



yojoelay -> RE: Morris Mustang scratch build (1/7/2008 6:15:01 AM)

One more thing (sorry for the multiple posts) - control throws don't seem to be listed on the plans. Anyone know what they should be?

Thanks again,

Joel



yojoelay -> RE: Morris Mustang scratch build (1/10/2008 3:10:37 AM)

Right - here is a proud moment. The servos install is just about done.

First picture below is of the stab and rudder servos. They are mounted on a hatch that screws into the top of the wing. The second picture is from the bottom of the wing, showing how all the servos fit in their own little hatches. On the left side of the wing (actually the right panel) you can see the throttle servo and it's linkage that extends through the leading edge. On the right side (the left panel) is the stab and rudder servos, with those flexible pushrods I reclaimed from an old beat up Cub.

If I was to do it again I'd get rid of the hatches and just flush mount everything - that was too much work.

Still wouldn't mind any measures/estimates for setting up the control throws - this is my first fun fly and the control surfaces are large enough to be slightly intimidating.

I have well and truly lost count of the hours invested. At a guest I'd say I'm well over 35-40 hrs right now and most of the building is done. The servos took a lot of screwing around.

I picked a color scheme - we'll see how it goes. I'm going to do a bit of a take on the Miss America Reno Racer Mustang with the red white and blue, but I'm going to try and make it 'Aussie' by arranging the stars in the shape of the Southern Cross, plus anything else I can think of along the way. Still have time to think about it as there is a bit of sanding and filling to do yet.

Joel



yojoelay -> RE: Morris Mustang scratch build (5/4/2008 1:07:02 PM)

Well, after letting this thread almost die off I figured it would be good to close the loop.

The Mustang got a maiden in and a few flights under the guidance of yours truly. It was my first scratch build, my second actual build, and frankly I couldn't wipe the smile off my face all day long. My fiancee is completely over hearing about it.

As for the flight report, well it was awesome. The plane is very 'point and shoot' without being twitchy, and with a broad speed envelope. More aerobatic than 3D, I have a Katana V2 46 and this feels more solid in the air. Flat out it cruises along with most other sport planes in the field (mine has an OS 46AC with an 11*6 prop at this stage), but cut the throttle and it just floats in. The only airplane I've seen float slower was an electric balsa / carbon fibre thingo - can't remember who made it. Landing is almost as simple as dropping the throttle and holding a very little bit of elevator. With a bit of trim I think you could set up the landing, put the transmitter down and let it land itself. Take off is 1/2 throttle and it flies with 1/4 throttle. Haven't really done much yet other than a couple of circuits, loops and some very quick rolls.

That nice light balsa I mentioned above gave me fits towards the end. I guess the lesson is in wood selection, something I'll get my head around for the next one. Anyways, the nice, super light built up elevators and ailerons couldn't handle the covering and as soon as the iron hit them they began bending and bowing, and I just couldn't get them to stay straight. Anyways, in the end I gave up and traced them onto a sheet of balsa and cut out solid pieces. Once mounted on the plane it balanced nearly perfectly so the weight gain really didn't make much difference.

The day ended abruptly when my rock solid motor dead sticked for no good reason - not sure why. The descent was completely controlable but someone was out on the strip picking up a plane that died on take off and there was no where to go. I tried to pull a 180 to land on the circuit going the other way but it lost too much altitude so I was forced to drop it into some tall grass, which tore off the landing gear on the left side. Looking back, the landing gear mounts weren't as good as they could have been, so I'm working on a few ideas right now.

In the process I've learned a few lessons:

1 - building takes a lot of time but the result is absolutely worth it. Having an ARF on the side helped so I could take my time
2 - keep it simple - I tried to hide the servos in the wing with fancy hatches - total waste of time. Should have gone with the easiest option and surface mounted them. Getting the covering on was enough screwing around, I still haven't finished the Southern Cross emblem. I tried Robart hinges - those plastic barbed ones that get inserted into a drilled hole - won't use them again until I have a drill press. In the end I replaced them with Dubro flat hinges - again, simple is best.
3 - Cheap servos are OK in this size plane. I used new Hitec 311's throughout - everything else I own has better servos and it made nno difference - this plane feels great
4 - Bigger surfaces are no problem. In the end I added 30% more area to the rudder and stab without any problems. The maiden was very sensitive but after dialing in 35% expo and dropping the linkages to the bottom hole on each control horn, everything was fine
5 - landing gear has to be the most robust part - see 'keep it simple' above - I mounted the landing gear in the wings and it snapped off at the first sign of a hard landing. I see some music wire gear getting bent up in the near future if this repair job doesn't hold. Because my field is so busy I don't fancy hand launching or retrieval so the belly pan landings are out
6 - wood selection - must get this sorted as the built up surfaces were way too flimsy to handle flight.

Anyways, I'll try and get some pictures soon. The plane is on charge right now and flying starts at 7am tomorrow moring.

Joel



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