1/7 Top Flite P-51D profile issues
04-28-2006, 09:26 PM
#26
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RE: 1/7 Top Flite P-51D profile issues
How much do the fans, batteries,ect. add to the weight? Pretty critical in the 1/7 scale. Not so much in 1/5 an bigger. IMHO
05-02-2006, 11:46 AM
#27
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RE: 1/7 Top Flite P-51D profile issues
Well, I'm back from my camping trip.
Let me respond to a few posts that were made while I was away:
1)
The RCV support folks have declared that the inlet on the TS P-51D 1/7 is indeed large
enough, PROVIDED that a large enough exit area is created. (gozouta)
Those fans
could in fact slow the air down, instead of promoting airflow. Testing will be essential.
As for the long duct to the rear of the airplane, I would like to try some ideas but I am
concerned about the long passageway that will be required. Fluid Dynamics theory states
that pipe losses (caused by drag on the pipe walls) can be very large. Maybe the air won't
flow through it at all! I think it will be very important to have a duct that is as wide and
straight as possible. Corners are especially bad for pressure buildup.
2)
I've mulled that one over a few times. Seems a little complicated for my level of experience,
but I would imagine that greatest challenge would be the additional weight from the pump,
piping, radiator, and the coolant itself. I would love to see a working version of this idea.
3)
I can provide front views. I'll post them on this thread in the near future. I'm using Photoshop
with various 2D layers. They are marginally accurate, to within 10% of scale I would estimate.
4)
It is a 4-inch spinner. Isn't that scale? Or does the drawing just show it as the incorrect size?
5)
Each fan weighs about 1 ounce. The battery pack consists of 8 AAA betteries which
will power all four fans four about 70 minutes. It weighs in at just over 4.5 ounces.
So about 8.5 ounces (1/2 lb) for the whole cooling system. Weight is a definite
drawback. I'm going to look for way to lighten the airframe with carbon fiber members, etc.
Regards,
WH
Let me respond to a few posts that were made while I was away:
1)
ORIGINAL: Jimmbbo
The challenge I see in the P51 is that the "gozinta" area is almost nonexistent, while there are possibliites for an engineering solution to get the "gozoutas" set up (duct to the aft radiator exit, f'rinstance)
The challenge I see in the P51 is that the "gozinta" area is almost nonexistent, while there are possibliites for an engineering solution to get the "gozoutas" set up (duct to the aft radiator exit, f'rinstance)
enough, PROVIDED that a large enough exit area is created. (gozouta)
Those fans could in fact slow the air down, instead of promoting airflow. Testing will be essential.
As for the long duct to the rear of the airplane, I would like to try some ideas but I am
concerned about the long passageway that will be required. Fluid Dynamics theory states
that pipe losses (caused by drag on the pipe walls) can be very large. Maybe the air won't
flow through it at all! I think it will be very important to have a duct that is as wide and
straight as possible. Corners are especially bad for pressure buildup.
2)
ORIGINAL: Stickbuilder
has anyone ever considered using a jacketed marine engine, and a real heat exchanger and a small pump to circulate the coolant
has anyone ever considered using a jacketed marine engine, and a real heat exchanger and a small pump to circulate the coolant
but I would imagine that greatest challenge would be the additional weight from the pump,
piping, radiator, and the coolant itself. I would love to see a working version of this idea.
3)
ORIGINAL:rc34074
IL2windhawk - how does the front view compare to the full scale? I would like to see this also. Are you using a cad system for these comaprisons? how accurate do you think these views are?
IL2windhawk - how does the front view compare to the full scale? I would like to see this also. Are you using a cad system for these comaprisons? how accurate do you think these views are?
with various 2D layers. They are marginally accurate, to within 10% of scale I would estimate.
4)
ORIGINAL:chad veich
You may have a bit less work to do if you enlarge your three view to match the scale of the airplane. It appears as though you have enlarged the drawing to match the spinner size of the TF kit. Problem is, the spinner shown on the TF kit is too small to be scale which is one of the reasons the nose looks so bad.
You may have a bit less work to do if you enlarge your three view to match the scale of the airplane. It appears as though you have enlarged the drawing to match the spinner size of the TF kit. Problem is, the spinner shown on the TF kit is too small to be scale which is one of the reasons the nose looks so bad.
5)
ORIGINAL:TLC Flying
How much do the fans, batteries,ect. add to the weight? Pretty critical in the 1/7 scale. Not so much in 1/5 an bigger. IMHO
How much do the fans, batteries,ect. add to the weight? Pretty critical in the 1/7 scale. Not so much in 1/5 an bigger. IMHO
will power all four fans four about 70 minutes. It weighs in at just over 4.5 ounces.
So about 8.5 ounces (1/2 lb) for the whole cooling system. Weight is a definite
drawback. I'm going to look for way to lighten the airframe with carbon fiber members, etc.
Regards,
WH
05-02-2006, 12:23 PM
#28
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RE: 1/7 Top Flite P-51D profile issues
You know, a different set of 3-views may fit completely different. A friend is doing a scale Mustang for competition and every set of 3-views is different. Not sure which ones are best. seem that when refering to pics, every set has some flaws.
05-02-2006, 09:07 PM
#29
RE: 1/7 Top Flite P-51D profile issues
In my case, in regards weight, the TF Spit suffers from a common problem of being tail heavy. I am able to house the ducted fan, esc, and battery all under the cowl. I'll be the ever optimist, and call this weight, useful ballast. I just hope there's still enough room up there if I have to add some lead. I plan on making further improvements to the baffles inside the front of the cowl too.
Scott
Scott
05-03-2006, 12:24 AM
#30
RE: 1/7 Top Flite P-51D profile issues
In my search on three views every set is different from one another because of individual and personal licence. Each person has a concept of what looks right (eye of the beholder) and many scale contests only judge on the drawings they are given (at least the judges are supposed to) that is also up for interpretation. So find a set that looks right to you and go from there. and enjoy building. That is finally what we had to do in designing our A model mustangs.
Tim
some pics
Tim
some pics
05-03-2006, 01:09 AM
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RE: 1/7 Top Flite P-51D profile issues
Hi
Are your Mustangs going have a glass fuz or are they going to be balsa? And that is a nice looking club.
shafs
Are your Mustangs going have a glass fuz or are they going to be balsa? And that is a nice looking club.
shafs
05-03-2006, 09:34 PM
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RE: 1/7 Top Flite P-51D profile issues
before this gold edition Mustang was released for sale the Beta builder entered a Scale Masters qualifier and used this plane to help him qualify for the big event.
He used a different spinner and a different brand of retracts and struts and special wheels. It was done in the Big Beautiful Gal with custom decals [ read preproduction] and Monocote and some paint.
He was very happy with the static scores that he was getting also.
It just goes to show that his documentation matched what he did.
tom
He used a different spinner and a different brand of retracts and struts and special wheels. It was done in the Big Beautiful Gal with custom decals [ read preproduction] and Monocote and some paint.
He was very happy with the static scores that he was getting also.
It just goes to show that his documentation matched what he did.
tom
01-21-2008, 11:32 AM
#34
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RE: 1/7 Top Flite P-51D profile issues
I've got the "dead-nuts" scale profile of the NA-73X, P-51A should anyone be interested.
email m: [email protected]
email m: [email protected]
01-21-2008, 12:38 PM
#35
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RE: 1/7 Top Flite P-51D profile issues
ORIGINAL: tdstaf
In my search on three views every set is different from one another because of individual and personal licence. Each person has a concept of what looks right (eye of the beholder) and many scale contests only judge on the drawings they are given (at least the judges are supposed to) that is also up for interpretation. So find a set that looks right to you and go from there. and enjoy building. That is finally what we had to do in designing our A model mustangs.
Tim
some pics
In my search on three views every set is different from one another because of individual and personal licence. Each person has a concept of what looks right (eye of the beholder) and many scale contests only judge on the drawings they are given (at least the judges are supposed to) that is also up for interpretation. So find a set that looks right to you and go from there. and enjoy building. That is finally what we had to do in designing our A model mustangs.
Tim
some pics
BINGO!!! Just because a set of three-views are published, dosen't make them "accurate" Just like Tim says - find a set you want to use and build to match. I'm a certified Scalemaster's judge and I always go by the supplied contestant's three-views even if I know that the three-view are not entirely accurate. I'm not judging the documentation, I'm judging how well the model matches the documentation.
