A new summer hat for demons
07-01-2009, 01:54 AM
#1
Thread Starter
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
A new summer hat for demons
Hi folks,
Time to hit the sack! But I had a late night creative surge, so I drew up cowl templates on AutoCAD, which have been grafted around drawings of the Jett 60LX (actually, all Jett .40 block series I suppose) and a Nelson FISE .40. Grafted those to a ply spine, added blocks to the side, did a little jig with the scroll saw, then sanded merrily away for a few minutes and voila. The blocks for the engine apron and tank cover are seen there in rough form where they shall stay overnight. So.. this is supposed to end up being a plug for a neat little accessory fiberglass cowl to set on top of a Screamin Demon to cover up it's big ugly metal head but let a little air through to cool its nostrils. Whatchoo think so far? I get the first 5.
'nite all [sm=sleeping.gif]
MJD
Time to hit the sack! But I had a late night creative surge, so I drew up cowl templates on AutoCAD, which have been grafted around drawings of the Jett 60LX (actually, all Jett .40 block series I suppose) and a Nelson FISE .40. Grafted those to a ply spine, added blocks to the side, did a little jig with the scroll saw, then sanded merrily away for a few minutes and voila. The blocks for the engine apron and tank cover are seen there in rough form where they shall stay overnight. So.. this is supposed to end up being a plug for a neat little accessory fiberglass cowl to set on top of a Screamin Demon to cover up it's big ugly metal head but let a little air through to cool its nostrils. Whatchoo think so far? I get the first 5.
'nite all [sm=sleeping.gif]
MJD
07-01-2009, 10:12 AM
#5
Senior Member
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: A new summer hat for demons
ORIGINAL: soarrich
Looks good. You might want to increase the fin size to compensate for the forward area.
Looks good. You might want to increase the fin size to compensate for the forward area.
07-01-2009, 12:16 PM
#6
Thread Starter
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: A new summer hat for demons
ORIGINAL: Mike Connor
I would think this would add to the Vertical Tail Volume Coefficient.
ORIGINAL: soarrich
Looks good. You might want to increase the fin size to compensate for the forward area.
Looks good. You might want to increase the fin size to compensate for the forward area.
MJD
07-01-2009, 12:31 PM
#7
Senior Member
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: A new summer hat for demons
ORIGINAL: MJD
...so I am not sold on how much net destabilization there really will be. I plan to toss it as is. If it isn't enough I'll fix it.
MJD
...so I am not sold on how much net destabilization there really will be. I plan to toss it as is. If it isn't enough I'll fix it.
MJD
07-01-2009, 12:50 PM
#8
RE: A new summer hat for demons
ORIGINAL: Mike Connor
My point is there shouldn't be any destabilization. Unless I am missing something here.
ORIGINAL: MJD
...so I am not sold on how much net destabilization there really will be. I plan to toss it as is. If it isn't enough I'll fix it.
MJD
...so I am not sold on how much net destabilization there really will be. I plan to toss it as is. If it isn't enough I'll fix it.
MJD
07-01-2009, 01:05 PM
#9
RE: A new summer hat for demons
MJD, your cowl looks real good. I'd think it would be pretty tough to make any money off hand laid cowels? By the time you go through all the steps, you could have laid up half a purpose built speed plane's fuselage. At the rate I get stuff done, I'd have to charge $300 just to break even 
07-01-2009, 02:10 PM
#11
Thread Starter
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: A new summer hat for demons
ORIGINAL: Lownverted
Vertical area ahead of the cg/cp is destabalizing.
Vertical area ahead of the cg/cp is destabalizing.
Mike C - oh yeah, you did mean you thought it would improve the picture didn't you? Now I get it.. ;-)
CP - you are quite right, unless I charge enough money to scare people. I want them myself though - always a good motivator - and I'll find out if I can offer them for a reasonable figure. I'll call it R&D for now.. not fooling around.. [8D]
MJD
07-01-2009, 03:08 PM
#13
RE: A new summer hat for demons
Even though there was area there, (albeit dirty) the fact is by cowling it in, you are adding substantial area ahead of the cp/cg. Simply by the addition of the area, there will be some affect on stability. You have also reduced drag, so likely it will be a wash. There is plenty of tail, I'll bet probably won't notice any difference, but make no mistake there is a change.
BTW..it looks super cool
BTW..it looks super cool
07-01-2009, 04:52 PM
#14
Thread Starter
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: A new summer hat for demons
ORIGINAL: Lownverted
Even though there was area there, (albeit dirty) the fact is by cowling it in, you are adding substantial area ahead of the cp/cg. Simply by the addition of the area, there will be some affect on stability. You have also reduced drag, so likely it will be a wash. There is plenty of tail, I'll bet probably won't notice any difference, but make no mistake there is a change.
BTW..it looks super cool
Even though there was area there, (albeit dirty) the fact is by cowling it in, you are adding substantial area ahead of the cp/cg. Simply by the addition of the area, there will be some affect on stability. You have also reduced drag, so likely it will be a wash. There is plenty of tail, I'll bet probably won't notice any difference, but make no mistake there is a change.
BTW..it looks super cool
Yeah, I guess I can see how the cleaned up and greater side area would be more efficient at generating "bad" lift (ahead of the CG) in the lateral plane, wouldn't it? I was thinking about drag in the lateral direction being less.
Progress pics: The plug so far sitting in top of the fiberglass apron I molded to the top surface earlier. These will be bonded together now, and fairing puttly blathered in all the junctions and squidged into shape with my best old white TF nylon 10-6 filleting tool.
MJD
re: the brick - I really didn't want the wind to blow it off the sawhorses again.
07-01-2009, 04:56 PM
#15
Thread Starter
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: A new summer hat for demons
I meant to point out - it is a PITA thinking about a nice cowl nose shape, when you have to consider the big ugly blobs that R/C carbs really are on the front of the engine. I'd have to carve a goiter into the front of the cylinder jacket to allow for every size and shape out there I think.. So anyhow I stretched the top profile forward, leaving it perhaps overall a bit fatter than optimum (no kidding?) but certainly not all that bad, and I am fairly sure it will be a net improvement. The cylinder jacket is a NACA 0035 btw. Not a great speed airfoil for wings.
MJD
MJD
07-01-2009, 06:56 PM
#17
Thread Starter
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: A new summer hat for demons
ORIGINAL: combatpigg
MJD, don't forget that some of the real goooood APC props have blades that extend to the rear of the spinner backplate.
MJD, don't forget that some of the real goooood APC props have blades that extend to the rear of the spinner backplate.
MJD
07-01-2009, 07:15 PM
#18
RE: A new summer hat for demons
It will most likely be a nice fit between the LE and the back of one of those props after you trim the forks off. When you were talking about clearance for a carb, I thought you might be talking about making the cowl bigger up front......then there would be a clearance problem.
The best solution of course is to remove the carb and sell it to a 90 year old speed freak, then set the plane up with a venturi.
The best solution of course is to remove the carb and sell it to a 90 year old speed freak, then set the plane up with a venturi.
07-01-2009, 09:09 PM
#20
Thread Starter
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: A new summer hat for demons
ORIGINAL: combatpigg
It will most likely be a nice fit between the LE and the back of one of those props after you trim the forks off. When you were talking about clearance for a carb, I thought you might be talking about making the cowl bigger up front......then there would be a clearance problem.
The best solution of course is to remove the carb and sell it to a 90 year old speed freak, then set the plane up with a venturi.
It will most likely be a nice fit between the LE and the back of one of those props after you trim the forks off. When you were talking about clearance for a carb, I thought you might be talking about making the cowl bigger up front......then there would be a clearance problem.
The best solution of course is to remove the carb and sell it to a 90 year old speed freak, then set the plane up with a venturi.
Some more progress pics. The goo is too plastic to sand yet, but a good time to snip and trim a few things. So far it fits nicely. There's gotta be a couple of mph in this thing, I hope.
MJD
07-02-2009, 11:15 AM
#23
Thread Starter
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: A new summer hat for demons
Sanded second coat of fairing putty, shot some primer on to look for all the booboos. I didn't zoom in enough for you to see them.. 
Now I'm liking it. It should even look cool with a rear header poking out coupled to a pipe. If this works out I will mess with the full meal deal, i.e. fully enclosed pipe. As is should be perfect for any of those old nitro guzzling AMA pylon engines with mini pipes. Wish I had one. Wish I knew someone who wanted one of aircraft so bad (yeah right) they'd barter for one. Dream on buddy.
MJD
Now I'm liking it. It should even look cool with a rear header poking out coupled to a pipe. If this works out I will mess with the full meal deal, i.e. fully enclosed pipe. As is should be perfect for any of those old nitro guzzling AMA pylon engines with mini pipes. Wish I had one. Wish I knew someone who wanted one of aircraft so bad (yeah right
) they'd barter for one. Dream on buddy.MJD
07-02-2009, 12:11 PM
#24
RE: A new summer hat for demons
Looks very studdly. If you showed up at our club field with that beast the parking lot would be empty before you could spit.
I'll bet your plane will need an air filter to keep chunks of Cermark F-16s out of it's stool.
Keep up the faith looking for old F-1 engines, they're out there.
In your travels if you see a K&B 6.5cc P/L set, let me know!
I'll bet your plane will need an air filter to keep chunks of Cermark F-16s out of it's stool.
Keep up the faith looking for old F-1 engines, they're out there.
In your travels if you see a K&B 6.5cc P/L set, let me know!
07-02-2009, 09:23 PM
#25
Thread Starter
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: A new summer hat for demons
ORIGINAL: combatpigg
I'll bet your plane will need an air filter to keep chunks of Cermark F-16s out of it's stool.
I'll bet your plane will need an air filter to keep chunks of Cermark F-16s out of it's stool.