P-6E Curtis hawk (build thread)
12-24-2014, 12:49 PM
#1727
Fiber glassing for reinforcing cowl:
Can any one point me to some directions for the proper technique for glassing the cowl on my P6-E,looking to cut a large hatch in the top as previously pictured here. Not repairing just looking to make it sturdier when I cut access hatch for batteries. Will be using 2oz cloth and epoxy. Maybe even a video.
Bob
Can any one point me to some directions for the proper technique for glassing the cowl on my P6-E,looking to cut a large hatch in the top as previously pictured here. Not repairing just looking to make it sturdier when I cut access hatch for batteries. Will be using 2oz cloth and epoxy. Maybe even a video.
Bob
01-12-2015, 11:10 AM
#1728
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Bob,
Sorry, I've been busy, hope you're still out there. As far as I know, there's not much more to it than cutting the cloth to fit, laying it in there, and brushing the epoxy on to it, working it in to make sure it wets through the cloth thoroughly. Since this isn't a visible area, it isn't necessary to do any more than that, unless you need to job to be as light as possible (probably not applicable here). Course, I've never competed in a beauty contest...
Sorry, I've been busy, hope you're still out there. As far as I know, there's not much more to it than cutting the cloth to fit, laying it in there, and brushing the epoxy on to it, working it in to make sure it wets through the cloth thoroughly. Since this isn't a visible area, it isn't necessary to do any more than that, unless you need to job to be as light as possible (probably not applicable here). Course, I've never competed in a beauty contest...
01-12-2015, 11:38 AM
#1729
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So I'm finally getting started with my build, after many months of being too busy. This will be fairly complicated as these assemblies go, as I intend to take full advantage of all the great ideas many of you have posted on this thread, for the tail wheel, rudder servo mounting, dihedral setting, etc. But I am also going off on my own in a number of ways. Please bear with me as to the frequency of updates, as I lead a busy life and may go several days between work sessions.
To start with, as I observed here quite a while ago, there is plenty of room to mount several reasonable sized engines vertically, with the issue then becoming cooling. I have some ideas how to handle that, but now that I have a kit and the engine I want to use, I can prove it.
As to the engine, I tend to take what Great Planes advises as accurate, and thus a 1.20-4S-sized engine should work out nicely. I also tend to build as light as possible, so based on that info and what I've read here, I am confident a DLE-20RA will work fine. This is what I purchased, and a quick check shows that it indeed will fit:
So using standard measuring, marking and remeasuring techniques, I utilized a Hangar 9 HAN2033 Ultra Mount and hung it on the nose to check for size and positioning.
As you can see, it definitely fits. In fact, I checked with more careful measurement and a FA-150 will fit, so you can go even larger this way if need be.
To start with, as I observed here quite a while ago, there is plenty of room to mount several reasonable sized engines vertically, with the issue then becoming cooling. I have some ideas how to handle that, but now that I have a kit and the engine I want to use, I can prove it.
As to the engine, I tend to take what Great Planes advises as accurate, and thus a 1.20-4S-sized engine should work out nicely. I also tend to build as light as possible, so based on that info and what I've read here, I am confident a DLE-20RA will work fine. This is what I purchased, and a quick check shows that it indeed will fit:
So using standard measuring, marking and remeasuring techniques, I utilized a Hangar 9 HAN2033 Ultra Mount and hung it on the nose to check for size and positioning.
As you can see, it definitely fits. In fact, I checked with more careful measurement and a FA-150 will fit, so you can go even larger this way if need be.
Last edited by RickVB; 01-12-2015 at 12:34 PM.
01-12-2015, 11:57 AM
#1730
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The reason I am starting with the engine is because I decided I must use a Keleo exhaust with this; they are just too cool to do without. The problem there is he won't make them anymore, but I got lucky and found one with a guy who never built his and didn't need it anymore. Kelvin was at first reluctant to go through with completing the system, as the original owner had purchased it about five years ago, but he eventually agreed, but I feel I better hurry up before he changes his mind. What you get with this exhaust kit is pictured here:
Actually, the center bottom piece is the stock DLE exhaust, which I'm considering using as a header, and I also left out the second flexible pipe in the kit. So you are somehow to configure this to fit, send the parts back to Keleo for final welding and powder coating, and then voila, you have a cool exhaust. It comes with instructions including photos, that first have you create a mount plate to attach the exhaust to, which goes on top of the motor mount.
I cut this out of 1/4" ply as instructed, but decided to attach it temporarily with screws, as I am concerned with the final configuration of it after mounting batteries, servos, etc., and the resulting airflow through the engine compartment. I will epoxy this when everything is finalized.
So the exhausts will fit something like this.
Actually, the center bottom piece is the stock DLE exhaust, which I'm considering using as a header, and I also left out the second flexible pipe in the kit. So you are somehow to configure this to fit, send the parts back to Keleo for final welding and powder coating, and then voila, you have a cool exhaust. It comes with instructions including photos, that first have you create a mount plate to attach the exhaust to, which goes on top of the motor mount.
I cut this out of 1/4" ply as instructed, but decided to attach it temporarily with screws, as I am concerned with the final configuration of it after mounting batteries, servos, etc., and the resulting airflow through the engine compartment. I will epoxy this when everything is finalized.
So the exhausts will fit something like this.
Last edited by RickVB; 01-12-2015 at 12:35 PM.
01-12-2015, 12:17 PM
#1731
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So next to figure out the exhaust position, I need to mount the cowl. Positioning it over the mounted engine, I could see that I will a lot of trouble figuring it all out with cowl in the way. Since I'm required to slot the back edge of the cowl to slide over the exhaust when they are mounted, I figured I might just as well separate the cowl in to top and bottom pieces, so then I can mount the bottom and fiddle with the mount/exhaust/engine positions to my hearts content without interference. I pulled out my trusty razor saw, and first scored the outside in a line straight back from top edge of the exhaust opening to the back edge of the cowl, then cut carefully along this, then down the corner of the exhaust opening, then along the back of the opening (leaving the top of the opening on the top cowl piece). The back part of the opening, where the kit's fake exhaust would have been glued to, I will remove later. Did this on both sides...
Then comes the nerve-wracking task of cutting across the top front of the cowl, connecting the two side cuts. I made some minor slips a couple of times as you can see; has anyone checked to see if LustreKote black matches well? Clearly I will have to do some touch-up.
After about an hour, I had two pieces like this:
Then comes the nerve-wracking task of cutting across the top front of the cowl, connecting the two side cuts. I made some minor slips a couple of times as you can see; has anyone checked to see if LustreKote black matches well? Clearly I will have to do some touch-up.
After about an hour, I had two pieces like this:
01-12-2015, 12:29 PM
#1732
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Now I can mount the bottom of the cowl, and then fiddle with everything else. Then next issue I ran is to is that they put four hardwood strips on the inside of the fuse, where the cowl mounting screws were to be located. With the cowl cut like this, the upper strips (red arrows below) are above the bottom half, so I used some 1/2x1/4 stock to create two more mounting blocks inside the fuse behind the front former, against the next stringer down from the original strips (blue arrows below).
They end up below the hardwood strip (red arrow) next to the stringer (blue arrow) as pointed two by the arrow below, but there is no possible way to get a camera in there to get a picture of the actual block positions; you get the idea.
After doing this, I noticed positioning the lower cowl that the engine was nowhere near forward enough; I ended up putting 1/2" standoffs behind the mount to get it far enough. I can move the engine back some on the mount later to make fine adjustments. The current position is almost 6 1/4" from the firewall.
More later...
They end up below the hardwood strip (red arrow) next to the stringer (blue arrow) as pointed two by the arrow below, but there is no possible way to get a camera in there to get a picture of the actual block positions; you get the idea.
After doing this, I noticed positioning the lower cowl that the engine was nowhere near forward enough; I ended up putting 1/2" standoffs behind the mount to get it far enough. I can move the engine back some on the mount later to make fine adjustments. The current position is almost 6 1/4" from the firewall.
More later...
01-12-2015, 01:25 PM
#1733
Envious of that Keleo scale exhaust - wow is that is gorgeous! I recall that Kelvin had one of the original GP P6-E planes so he may have some affinity for this model.
I started my build with the DLE20RA as well, and in fact purchased and almost got to where you are. After sorting out CG issues, my build would have required more ballast than I had room for, so I switched to higher mass DLE35RA w/heavy 3-blade wood prop and still required 2.28 lbs of weight! The engines a decade ago must have been very, very heavy!
Again, that exhaust is fantastic! Cheers
I started my build with the DLE20RA as well, and in fact purchased and almost got to where you are. After sorting out CG issues, my build would have required more ballast than I had room for, so I switched to higher mass DLE35RA w/heavy 3-blade wood prop and still required 2.28 lbs of weight! The engines a decade ago must have been very, very heavy!
Again, that exhaust is fantastic! Cheers
01-12-2015, 03:00 PM
#1734
Rick,
Thanks for the info, I am electrifying my Hawk and need access to the top of the motor box,but with the demise of the kits and spare parts i.e.. cowl and LG pants have decided to take off the cowl in one piece every battery change. Will attempt to cut the cowl after I get some flights on her.
Bob
Thanks for the info, I am electrifying my Hawk and need access to the top of the motor box,but with the demise of the kits and spare parts i.e.. cowl and LG pants have decided to take off the cowl in one piece every battery change. Will attempt to cut the cowl after I get some flights on her.
Bob
01-12-2015, 04:24 PM
#1735
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...I started my build with the DLE20RA as well, and in fact purchased and almost got to where you are. After sorting out CG issues, my build would have required more ballast than I had room for, so I switched to higher mass DLE35RA w/heavy 3-blade wood prop and still required 2.28 lbs of weight! The engines a decade ago must have been very, very heavy!
). Of course, the 35RA is a completely different mount (radial), so I'd have to start over and redrill. I don't thing there are any other 60mm beam mount gas alternatives out there, so if I needed to go up a notch, I'm stuck converting to glow.How much did yours end up weighing all up?
Last edited by RickVB; 01-14-2015 at 07:56 AM.
01-14-2015, 03:22 PM
#1737
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Hey, does anyone have good photos of the cowl top scoop, the aileron link and bellcrank housing below it? (I know, I can get a good look at the AFM, but I don't have time to get to Dayton right now.)
01-15-2015, 09:50 AM
#1739
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Thanks Mark. I was looking for prototype photos to see what that looked like on the real plane. I'm going to open up that scoop regardless; I just wondered if there was anything I could do to dress it up to look more realistic.
01-15-2015, 11:26 AM
#1741
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So this just seems to show it as a plain sheet metal duct; I was hoping for something close to a straight on closeup to show any detail. I swear someone on this thread provided some detail photos at some point, but I can't find that now. Maybe I'm thinking of another thread.
01-16-2015, 11:23 PM
#1742
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Continuing on with the goal of coming up with the exhaust configuration, I mounted the lower cowl using the old "cards taped on the fuse" trick, as shown in the plane kit instructions. When I put the cowl on the fuse to position it for drilling, I carefully lined up the feathers before taping it in place, checking that the prop shaft was centered in the cowl hole. After drilling and threading screws into it, the cowl looked pretty good from close up, and the prop shaft was pretty well dead center.
However, the feathers don't look so good depending on the angle that you observe them... I really don't have a solution for this.
Also, I note my first underestimation - note below that the main air inlet, on the lower front of the cowl, is nearly directly below the front of the cylinder fins. So the air is going to have to be routed straight up in the cowl. I will have to be very clever with my ducting...
Checking the overall fit of the exhausts - two problems are apparent. First, it would probably be better if all the outlet pipes were about 1/4" shorter, then the manifolds could be shifted outboard more, leaving more space in the middle for airflow off the back of the cylinder. I'm not real hot on trying to recut 24 pipes to match as well as they do now, so I guess I'll have to let this go.
Finally, the outlet pipes will end up angled down at about 30 degrees below horizontal, whereas the plastic fake pipes would have been glued on the sides, facing up at about 20 degrees above horizontal. I'm not sure which is right, as I haven't seen a good closeup of the pipes on the real plane yet; but again I don't think there's anything I can do about it now. (By the way, I can't show you what the fake ones look like in contrast, because I either misplaced them or never had them.)
I couldn't resist slapping the prop on to see what this would look like...
However, the feathers don't look so good depending on the angle that you observe them... I really don't have a solution for this.
Also, I note my first underestimation - note below that the main air inlet, on the lower front of the cowl, is nearly directly below the front of the cylinder fins. So the air is going to have to be routed straight up in the cowl. I will have to be very clever with my ducting...
Checking the overall fit of the exhausts - two problems are apparent. First, it would probably be better if all the outlet pipes were about 1/4" shorter, then the manifolds could be shifted outboard more, leaving more space in the middle for airflow off the back of the cylinder. I'm not real hot on trying to recut 24 pipes to match as well as they do now, so I guess I'll have to let this go.
Finally, the outlet pipes will end up angled down at about 30 degrees below horizontal, whereas the plastic fake pipes would have been glued on the sides, facing up at about 20 degrees above horizontal. I'm not sure which is right, as I haven't seen a good closeup of the pipes on the real plane yet; but again I don't think there's anything I can do about it now. (By the way, I can't show you what the fake ones look like in contrast, because I either misplaced them or never had them.)
I couldn't resist slapping the prop on to see what this would look like...
Last edited by RickVB; 01-17-2015 at 05:44 PM.
01-17-2015, 07:46 AM
#1744
Is flipping the engine cylinder facing down an option? In my case (DLE35RA), this puts the fooling fins directly in line with lower cooling hole and puts the top of cylinder & plug slightly below the cowl for good air flow and access.
Oh yeah, those exhaust pipes are cool!
Cheers
Oh yeah, those exhaust pipes are cool!
Cheers
01-17-2015, 10:09 AM
#1746
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Is flipping the engine cylinder facing down an option? In my case (DLE35RA), this puts the fooling fins directly in line with lower cooling hole and puts the top of cylinder & plug slightly below the cowl for good air flow and access.
Oh yeah, those exhaust pipes are cool!
Cheers
Oh yeah, those exhaust pipes are cool!
Cheers
As I said here when I started this mess early last year, I really don't like cutting holes in a cowl at all if I can help it. As you can see in posting #1619 on page 65 of this thread, I did an experiment with Wile E's drawing of his FPE 1.3 installation, where I showed that the DLE-20 (same size) would fit with no cuts upright, while it will not fit without cuts inverted. Thus, here I am. You can properly cool an engine with very small inlets and proper ducting and outlets. So that's my plan as of now. We'll see I suppose.
01-20-2015, 10:16 PM
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So I just remembered Bryan Austin's (CurtissHawkP6E) wonderful photo postings starting on page 21 of this thread. Does anyone know what ever happened to him? His web site's gone, and with it all the videos and discussions on his forum referenced early in this thread.
01-20-2015, 10:34 PM
#1750
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A little more progress... cut down the exhaust slot; found that the edge over it on the top cowl piece also had to be trimmed to get it to fit. Not sure how far the pipes should extend...
Anyone know why a 12-cylinder engine needed 24 exhaust stacks?
View with the top off and the stacks set in:
Here's the header extrusion as provided bolted on. Obviously needs to be trimmed...
I've sent all the photos with a request for further instructions to Kelvin, so the engine compartment is on hold until I hear from him. Guess I'll start working on the wings tomorrow (potentially next big coloring outside the lines...)
Anyone know why a 12-cylinder engine needed 24 exhaust stacks?
View with the top off and the stacks set in:
Here's the header extrusion as provided bolted on. Obviously needs to be trimmed...
I've sent all the photos with a request for further instructions to Kelvin, so the engine compartment is on hold until I hear from him. Guess I'll start working on the wings tomorrow (potentially next big coloring outside the lines...)