I have the taste of Metal in my mouth!!!

[John]

Re: I have the taste of Metal in my mouth!!!

No it has not. They were just cut and filed. End of the tip is only rated for about mach.74. With the engine running at full pop the blades are going supersonic at the tip. About 4-5 inches of it. That is bad! We may loose some of that cool sound (or all of it), but hey I will take even 5 mph if it means a running engine on sunday night.

Years back the model airplane guys would sand the wooden props thinner to get more RPM.

I guess the difficult part(for the big birds) would be balancing the blades after modification. Hey you might get 5 mph out of it!

If PM can make 450 on the course(1988), what will it take to get into the 480's and 490's? It seems like every little bit of improvement would help...

[BillRo]

Re: I have the taste of Metal in my mouth!!!

When Formula Ones had metal props I obtained a transonic section from Northrop and modified the outer couple of inches of the Sensenich prop John Parker was using, and that was in the late 70's, so I am sure other people did the same. The IF1 website if1airracing.com has a Design Guide under "Rules" which includes a table for tip speed vs forward speed vs RPM. I seriously doubt that Unlimited prop tips are supersonic as they would make an excruciating noise audible for 5 miles. What is the prop diameter and rpm of a top Unlimited racer? You really want to keep tip speeds below M=.94 to avoid the associated drag rise, which will sap an amazing amount of power.

BillRo

[jarrodeu]

Re: I have the taste of Metal in my mouth!!!

I seriously doubt that Unlimited prop tips are supersonic as they would make an excruciating noise audible for 5 miles. What is the prop diameter and rpm of a top Unlimited racer? You really want to keep tip speeds below M=.94 to avoid the associated drag rise, which will sap an amazing amount of power.
BillRo

Supersonic tips is the reason they abandoned the turboprop powered F-84. Good performance for a prop driven aircraft but gave ground crews nausea.

Jarrod

[MRussell]

Re: I have the taste of Metal in my mouth!!!

I seriously doubt that Unlimited prop tips are supersonic as they would make an excruciating noise audible for 5 miles.

You mean like T-6s?

[Wild Bill Kelso]

Re: I have the taste of Metal in my mouth!!!

You mean like T-6s?

Or how you can hear Dago Red off the back valley! As for T-6's I have heard of someone doing some prop "stuff" this year. Keep an eye out for a nice speed increase in the T-6 class this year if they do.

[Wild Bill Kelso]

Re: I have the taste of Metal in my mouth!!!

Years back the model airplane guys would sand the wooden props thinner to get more RPM.

I guess the difficult part(for the big birds) would be balancing the blades after modification. Hey you might get 5 mph out of it!

If PM can make 450 on the course(1988), what will it take to get into the 480's and 490's? It seems like every little bit of improvement would help...

Money (Speed costs money... How fast you wanna go?)
Cooling Drag (Mainly stock cooling system)
Props (Coud be biggest hurdle)
Minor Airframe Clean-ups

[Leo]

Re: I have the taste of Metal in my mouth!!!

What prop mods can you get away wth in a stock class?
No secrets, just generally wondering.
I know there was an issue with pitch control being modified a few back and it was a no-no.

[Victor Archer]

Re: I have the taste of Metal in my mouth!!!

What prop mods can you get away wth in a stock class?
No secrets, just generally wondering.
I know there was an issue with pitch control being modified a few back and it was a no-no.

There's a stock T-6 Class

[Leo]

Re: I have the taste of Metal in my mouth!!!

Well, stock in theory...
Let me re-phrase that. What can you do to a prop that won't violate any rules, or at the least be noticed by the techies?
I used to "race" destruction derby for a number of years and we had all kinds of tricks that were not covered by a rule or just plain hidden...

[Wild Bill Kelso]

Re: I have the taste of Metal in my mouth!!!

What prop mods can you get away wth in a stock class?
No secrets, just generally wondering.
I know there was an issue with pitch control being modified a few back and it was a no-no.

That is what seperates hobby racers from career racers. The ability to find out what the limits of the rules are and how those limits can be bent, pushed, and streched. The trick is to not go too far... that's called cheating! I remember once when we used to run illegal fuel in our bikes during qualifing. The rules stated that you could not "race" with any fuel additives. Weeeeeeel that says nothing about qualifing now does it, but you got a better grid spot. The rule got rewritten, but hey it was fun while it lasted. Not what is going on here, but you catch my drift. Do you think most T-6's run stock tires. I know some run a bigger tire to fill up the wheel well gap just a tad more. There is a perfect example.

[Leo]

Re: I have the taste of Metal in my mouth!!!

And I've seen the mix and match of parts to get the cleanest config. The tweaking of the little things, filling screw holes with wax, etc.
I know there's a lot you can do to an engine without "altering" it.
Just figured the prop would be under a little stricter mod rules by both the races and the FAA, in this class.

[Uh-sure]

Re: I have the taste of Metal in my mouth!!!

All the T-6's are stock Victor, some are just "stocker".

Not much you can do on T-6 racing props- there are minimum and maximum lengths, but racers can twist the blades however they like as this is "at pilots discretion" in the rules.

In past years there have also been templates for blade profile.

It makes a huge difference finding the right prop/engine combination-
one prop that works GREAT on one racer might be 5-10mph slower on another. Most teams bring several props- for different conditions etc.

[speeddemon]

Re: I have the taste of Metal in my mouth!!!

All the T-6's are stock Victor, some are just "stocker".

Uh huh....and some of those are even 'stocker-er'!

[Uh-sure]

Re: I have the taste of Metal in my mouth!!!

stalker.......errrrr

[Wild Bill Kelso]

Re: I have the taste of Metal in my mouth!!!

Not much you can do on T-6 racing props- there are minimum and maximum lengths, but racers can twist the blades however they like as this is "at pilots discretion" in the rules.

Like I said bend the rule and the blade.