Aerodynamic modifications

[LoveOldPlanes]

Re: Aerodynamic modifications

Smaller dorsal... ?

Somebody noticed! Well, at least the right part. It flows much more nicely than before and is longer than it was. It blends in so much better than the original one did. It's a wonderful piece of work made in house.

[Wild Bill Kelso]

Re: Aerodynamic modifications

My thrill of this last year has been working with Thom on Team PM doing these mods. The great thing about it all is his excitement and passion to do better than has been done before. He loves air racing and the challenge of the engineering of the aircraft itself. The excitement is invigorating to be around. The scoop extension and strakes started life on Ridgerunner 3 and had to be adapted/ fitted to PM's airframe. Rather than poke new holes in the airframe, I spent when a fair amount of time doing fiberglass/ composite work to extend edges to accommodate existing holes in the airframe. Another Team member spent a fair amount of time getting the scoop extension to mount properly, so as to give the intended advantages. Its using the best of what we can come up with on our budget.

The wingtips were a new design that Thom came up with himself. He knew what he wanted, had the engineering work done and the tips created. The filling of the flush rivets in the wing was treated as sacrilege by many fans of the aircraft...until you remember it IS a Racing Aircraft and the mod was to make it faster. Lots of labor for small gains, but every little bit counts.

The canopy profile is actually close to the last one, with a differing hinge system and more glass to have a better view for the camera project. That said, I am still laughing to myself that thus far, everybody has missed a major aerodynamic mod to the airframe. A few months before the Races somebody in one of these threads was even going on at length about how bad the old design was. I had to bite my tongue to not talk about the mod were directly in the middle of making. I still wonder why nobody has mentioned it.

So far, the Team is recovering from last year and starting to get the excitement back for this year's challenges. I suspect only a couple of people have direct access to the data gained this year. I also think its important to note how PM, as a No Bucks Team was in the Gold next to Mega Bucks Teams. Hats of to all the Teams approaches, but I keep thinking about Team PM when I remember the line from the WW2 Seabees, "The Impossible Will Take Just a Little Longer....". I am most impressed with what Thom has done in just a few years of owning the aircraft....against Teams with decades of racing under their belts. While we have our shining stars like Wild Bill, others of us are getting the hang of thinking outside the box to help the program. As the program gets its feet under it, I am certain great things lay ahead- for the aircraft, the Team and Racing itself. Am I hooked worse than ever on Air Racing...? Oh heck yeah!

D
Those wingtips were not a design of Thom's in any way shape or form. Those were the brain child of Blue Foam, Matt Williams, and me. We wanted them on there years ago.

[LoveOldPlanes]

Re: Aerodynamic modifications

D
Those wingtips were not a design of Thom's in any way shape or form. Those were the brain child of Blue Foam, Matt Williams, and me. We wanted them on there years ago.

Good to know the extended details. All I remember was early in the year taking off the old tips to be ready for when the new ones came in, and Thom explaining what the expected benefits would be to them.

[John]

Re: Aerodynamic modifications

In RearBear's case, it includes the more powerful unseen spoiler drag effect of the shock wave, but they got it to still compete with the Mustangs that have a lesser effect.

Could you explain? -is this related to the overall cross sectional area of these aircraft?

Rare Bear is a Beast for sure!

[Wild Bill Kelso]

Re: Aerodynamic modifications

Somebody noticed! Well, at least the right part. It flows much more nicely than before and is longer than it was. It blends in so much better than the original one did. It's a wonderful piece of work made in house.

By who?! Come on man! We have names... Use them! What did he used to do? Who did he work for?!

[wyhdah]

Re: Aerodynamic modifications

By who?! Come on man! We have names... Use them! What did he used to do? Who did he work for?!

By the Carbon "Don" Don Pataky at P Factor Aviation Innovations who also made the kickass intake. He used to work on secret squirrel space shuttle stuff over on the governments team.

Oh and one of the many to work all nighters at hanger as well.

[Wild Bill Kelso]

Re: Aerodynamic modifications

By the Carbon "Don" Don Pataky at P Factor Aviation Innovations who also made the kickass intake. He used to work on secret squirrel space shuttle stuff over on the governments team.

Oh and one of the many to work all nighters at hanger as well.

It's time my boys get some credit for the awesome work they have done. They are coming along at a rapid pace.

[Curt_B]

Re: Aerodynamic modifications

Could you explain? -is this related to the overall cross sectional area of these aircraft?

Rare Bear is a Beast for sure!

Cross section of the fat fuselage comes into play if the widest part of the fuselage is over the wing. By the spoiler effect analogy, I meant that the spoiler separates the flow behind it, and the shock wave, when it gets so strong the pilot's checking the fillings in his teeth, causes a flow separation. This separation is called shock stall and because it occurs at such high q's, induces a rather severe vibration in the airframe. Generally, when this is felt by the pilot and becomes objectionable, it helps define the buffet boundary of the airplane. You'd get similar vibrations, and drag, by deploying a spoiler at high speed. As you get deeper and deeper into the drag rise, the subsonic drag of the airplane due to the fat fuselage in the Rear Bear's case, becomes less significant. But the fat part of the fuselage occurring over the wing, (if that's the case for Rear Bear), where the shock is, will make the shock stronger sooner and decrease drag divergence Mach number of the airplane.
r


Flow separation occurs beyond drag divergence Mach number. The boundary layer going through the rapid pressure compression of the shock thickens suddenly and continues to grow rearward but the flow is still attached. This rapid growth of the boundary layer reduces the pressure recovery on the wing and causes the drag to increase.

[Curt_B]

Re: Aerodynamic modifications

The PM guys also added pieces to smooth out the line by the coolant exit door. Used to come to a squared off end.

Since we're taking names, who made that. Got to feel the curved inner piece of that, and couldn't stop it felt so smooth.

[Wild Bill Kelso]

Re: Aerodynamic modifications

Since we're taking names, who made that. Got to feel the curved inner piece of that, and couldn't stop it felt so smooth.

Thom made that, and it was a nice add on. the old exit was creating some angry pissed off air.

[AAFO_WSagar]

Re: Aerodynamic modifications

Thom made that, and it was a nice add on. the old exit was creating some angry pissed off air.

Oh God... really... Pissed off... How I hate pissed off air!!!

[Wild Bill Kelso]

Re: Aerodynamic modifications

Oh God... really... Pissed off... How I hate pissed off air!!!

One of these days I'm going to write a book on Air Race Slang.

Chapter 1: The **** Kerch says

Chapter 2: The eloquent rantings of Don Dull

Chapter 3: Yes I do know what Blue Foam is saying

Chapter 4: I don't know what Pete Law just said but I need to turn this in a 1/4 turn

Chapter 5: Someone give Stavrakakis a telepromtor please

[AAFO_WSagar]

Re: Aerodynamic modifications

Chapter 5: Someone give Stavrakakis a telepromtor please

[John]

Re: Aerodynamic modifications

Cross section of the fat fuselage comes into play if the widest part of the fuselage is over the wing. By the spoiler effect analogy, I meant that the spoiler separates the flow behind it, and the shock wave, when it gets so strong the pilot's checking the fillings in his teeth, causes a flow separation. This separation is called shock stall and because it occurs at such high q's, induces a rather severe vibration in the airframe. Generally, when this is felt by the pilot and becomes objectionable, it helps define the buffet boundary of the airplane. You'd get similar vibrations, and drag, by deploying a spoiler at high speed. As you get deeper and deeper into the drag rise, the subsonic drag of the airplane due to the fat fuselage in the Rear Bear's case, becomes less significant. But the fat part of the fuselage occurring over the wing, (if that's the case for Rear Bear), where the shock is, will make the shock stronger sooner and decrease drag divergence Mach number of the airplane.
r
[ATTACH=CONFIG]20246[/ATTACH]

Flow separation occurs beyond drag divergence Mach number. The boundary layer going through the rapid pressure compression of the shock thickens suddenly and continues to grow rearward but the flow is still attached. This rapid growth of the boundary layer reduces the pressure recovery on the wing and causes the drag to increase.

Thanks, very educational, that looks like a supercritical airfoil(?) What other areas on the unlimiteds could use attention?

[Curt_B]

Re: Aerodynamic modifications

Thanks, very educational, that looks like a supercritical airfoil(?) What other areas on the unlimiteds could use attention?

There're some regions of thick boundary layer growth on the Mustangs that could be squeezed without penalty to improve pressure recovery and give more speed. Talking one or two specifics, CheckMate could use some clean-up touches. The turtle deck on the Mustangs intersects the fuselage at a crisp angle. If that intersection was roundy, like Precious Metal's new turtle deck mod, they'd go a little faster. If there's room to make Rear Bear's canopy smaller, they'd improve the area rule and that'd help out a little transonically. There are some other places that could use attention. The largest improvement would be to reduce compressibility drag. Then there's some improvements to propeller technology that'd help.

Anybody else notice anything, or want to chime in? Good subject. We should extend it to include all classes.