p-51 racer qustion

[BEARCLAW777]

i have a Good question about the p-51 the air intake on the front of the plane right below the spinner. on dago red strega voodoo and others was it modified?? and if so how

[Big_Jim]

Re: p-51 racer qustion

i have a Good question about the p-51 the air intake on the front of the plane right below the spinner. on dago red strega voodoo and others was it modified?? and if so how

Any modification is most likely internal...with a composite duct or something, to get a smooth airflow.

[BEARCLAW777]

Re: p-51 racer qustion

yea it is hard to tell some times what body modifications they make externally to the mustangs

[GHOSTRIDER]

Re: p-51 racer qustion

the air intake on the mustang is for the carberator. externally, there are no modifications, as there is a certain amount of cfm's required to
asperate and atomotize the beast above. internally several ducting
units have been modifed or remanufactured from fiberglass or carbon
fiber. not necessarily to smooth the air flow but more to lighten the airframe. the original units were heavy-duty aluminum, about 42lbs.
the carbon fiber one is three times more expensive, three times stronger, and weighs only 12 lbs, or so.
maybe we can get bruce lockwood to chime in here?- I took the ducting off of Dago Red one day in 1989, handed it to Bruce, said "I bet you could make one of these out of fiber glass". a year later Dago returned to reno "enilghtened".

[Sparrow]

Re: p-51 racer qustion

The smile at the carb air inlet under the spinner is not modified. Several have tried differant configurations and for the most part have found that it works as is. The main reason for the single piece intake trunk is to reduce air leakage between the smile & the carburator. It doesn't take much air loss in that area to effect overall boost the engine will generate with the benefit of ram air. The stock aluminum ducting leaks like a sieve.

[WARPT]

Re: p-51 racer qustion

Good question!
And thanks to those that know to answer!
I love this stuff!

[race9]

Re: p-51 racer qustion

The only ones that I know that changed it were Precocious Metal, where the normal 'smile' intake was moved up top, like on an A-36, and Miss Ashley II, which I believe had a NACA scoop on top.

[Big_Jim]

Re: p-51 racer qustion

The only ones that I know that changed it were Precocious Metal, where the normal 'smile' intake was moved up top, like on an A-36, and Miss Ashley II, which I believe had a NACA scoop on top.

Red Baron, Precious Metal (2nd), and Miss Ashley II all had downdraft carburators for the Griffon. Tsunami and Vendetta had them as well for the Merlin.

I know for a fact that Vendetta turned the supercharger upside-down because of how the Lear wing fit the fuselage (ran out of room on the bottom of the firewall for the normal supercharger/induction trunk set-up. So I suppose the same would/could be said for MAII, since it used the same wing set-up. John Dilley told me that that was the only reason they had the scoop on top on Vendetta.

[jarrodeu]

Re: p-51 racer qustion

I know for a fact that Vendetta turned the supercharger upside-down because of how the Lear wing fit the fuselage (ran out of room on the bottom of the firewall for the normal supercharger/induction trunk set-up. So I suppose the same would/could be said for MAII, since it used the same wing set-up. John Dilley told me that that was the only reason they had the scoop on top on Vendetta.

I don't think Vendetta could have had a NACA style carb inlet if it was on the bottom of the engine could it?

Jarrod

[Randy Haskin]

Re: p-51 racer qustion

I don't think Vendetta could have had a NACA style carb inlet if it was on the bottom of the engine could it?

Jarrod

Do aerodynamics not work upside down?

[FuryFan]

Re: p-51 racer qustion

Do aerodynamics not work upside down?

Well duh!..................The air will fall out!

[jarrodeu]

Re: p-51 racer qustion

Do aerodynamics not work upside down?

I was thinking the angle would not work. It's fairly flat on top but the scoop would be pointing up if it was on the bottom. I guess not though.

Jarrod

[Race5]

Re: p-51 racer qustion

I was thinking the angle would not work. It's fairly flat on top but the scoop would be pointing up if it was on the bottom. I guess not though.

Jarrod

I think the scoop itself might work either way, but it still doesn't solve the interference fit issue with the wing. You would still have to have ducting from the scoop to the carb, and I think that was the main issue. I'm not even sure the carb would clear the wing attach if left mounted in stock down draft fashion.

[kiwiracefan]

Re: p-51 racer qustion

Im no aerodynamisct but from what reading ive done around the net and also the raceplane tech griffon mustang book, the NACA duct required extremely precise ramp angles and shapes to work properly.
If someone out there can correct me if im wrong, but from what i have read around the net was that the Vendetta NACA duct didnt work properly because the airflow came into the duct and imediately turned into the Carb where the Miss Ashley II duct worked really well because the airflow had time to straighten out and go into the carb smoother due to a longer inlet and smoother turn into the carb.

If i am wrong, please correct me... Maybe if Mr Slack, Mr jackson or Mr Lockwood could shed more light on it?