Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

No Damage

Reply

Old 12-01-2002, 12:45 AM
  #1  
AtomicFrawg
Senior Member
Thread Starter
My Feedback: (8)
 
AtomicFrawg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, LA
Posts: 227
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

Well here is some proof that the whiplash is strong
She went in at 130+mph The cntrl horn broke in flight
This is all the damage



A few scratches



Broke prop



The broken Cntrl Horn


Later
Chris
AtomicFrawg is offline  
Reply With Quote
Old 12-01-2002, 12:49 AM
  #2  
Daryl Lane
Member
 
Join Date: Sep 2002
Location: brandon, MS
Posts: 40
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

Chris if you have time tonight call me at 601-992-9686,need to order a new plane thanks daryl
Daryl Lane is offline  
Reply With Quote
Old 12-01-2002, 12:59 AM
  #3  
AtomicFrawg
Senior Member
Thread Starter
My Feedback: (8)
 
AtomicFrawg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, LA
Posts: 227
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

Is the website down? It would be faster to order online or call us on monday.
You liked it that much you now want another one?

thanks
Chris
AtomicFrawg is offline  
Reply With Quote
Old 12-01-2002, 01:50 AM
  #4  
George
My Feedback: (57)
 
Join Date: Dec 2001
Location: Va Beach, VA
Posts: 2,988
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default 2 Words

Metal horns

Seriously though, I'm sorry to see that happened, but looks like you faired well. Even if you hadn't, I bet you could have gotten another, NO PROBLEM (seeing that you build them).

George
George is offline  
Reply With Quote
Old 12-01-2002, 02:29 AM
  #5  
AtomicFrawg
Senior Member
Thread Starter
My Feedback: (8)
 
AtomicFrawg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, LA
Posts: 227
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

i think that those were the horns that flew on the prototype whiplash LOL And has been on 3 whiplashes since.

I guess i need new ones.

But it fared really well. the only damage was the broken prop
It hit really hard. I thought it was a goner.
Thank God i was not a full throttle That would not have been pretty, mine does 160+mph


Later
Chris
AtomicFrawg is offline  
Reply With Quote
Old 12-01-2002, 04:06 AM
  #6  
jlong34016
Senior Member
My Feedback: (1)
 
Join Date: Apr 2002
Location: columbus, OR,
Posts: 365
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default engine

Is that a rossi 45? What prop do you run? What rpm do you get out of it?
jlong34016 is offline  
Reply With Quote
Old 12-01-2002, 03:01 PM
  #7  
AtomicFrawg
Senior Member
Thread Starter
My Feedback: (8)
 
AtomicFrawg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, LA
Posts: 227
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

Yes it is a rossi 45. RPM's Im guessing in the 20000 range but i dont know for sure. Ill find out today.
My prop is a 9x7. It work for me.


Later
Chris
AtomicFrawg is offline  
Reply With Quote
Old 12-01-2002, 05:55 PM
  #8  
WRXlovr
Senior Member
 
Join Date: Jul 2002
Location:
Posts: 142
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

You could definatly get more speed out of that if you move down to an 8*7 or 8*8 prop because that 9 is WAY too much diameter.
WRXlovr is offline  
Reply With Quote
Old 12-01-2002, 07:47 PM
  #9  
AtomicFrawg
Senior Member
Thread Starter
My Feedback: (8)
 
AtomicFrawg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, LA
Posts: 227
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

Actually i have tried to go to the 8's and it wont pull the plane.
The 9x7 gave me the best speeds


Later
Chris
AtomicFrawg is offline  
Reply With Quote
Old 12-01-2002, 07:49 PM
  #10  
jlong34016
Senior Member
My Feedback: (1)
 
Join Date: Apr 2002
Location: columbus, OR,
Posts: 365
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default engine and prop

Uncle. You guys in LA win. You take a good standard engine slap a pipe and a 9x7 prop on it and fly like crazy. All the while i am trying to reinvent the wheel up here and going nowhere fast. I have that engine and a full length pipe sitting in the garage. I think i will bolt it on spiderman and just fly. Anyone want to buy a couple jetts and a few nelsons? 150-160 is really all i need.
jlong34016 is offline  
Reply With Quote
Old 12-01-2002, 07:57 PM
  #11  
ChuckAuger
Senior Member
My Feedback: (12)
 
Join Date: Dec 2001
Location: Pampa, TX
Posts: 5,133
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Welcome to the club,, Jlong..

LOL
ChuckAuger is offline  
Reply With Quote
Old 12-01-2002, 08:46 PM
  #12  
Dustflyer
My Feedback: (13)
 
Dustflyer's Avatar
 
Join Date: Dec 2001
Location: Abington, PA
Posts: 913
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Pictures

Atomic,

What I really want to know is how you are able to post those big pictures?
Dustflyer is offline  
Reply With Quote
Old 12-01-2002, 09:36 PM
  #13  
AtomicFrawg
Senior Member
Thread Starter
My Feedback: (8)
 
AtomicFrawg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, LA
Posts: 227
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

the pics are linked from a host webpage


Later
Chris
AtomicFrawg is offline  
Reply With Quote
Old 12-02-2002, 02:28 AM
  #14  
William Robison
Senior Member
My Feedback: (3)
 
Join Date: Nov 2002
Location: Mary Esther, Florida, FL
Posts: 20,205
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

Hey there, Nuclear Batrachian! (That's atomic frog to a dictionary fanatic)

Put a helmet cowl on it, (like the u/c speed planes) and fair the servos. How much speed do you think you would gain?

If it will take off with it, try a 7x12 prop. If it will pull it, at 70% prop efficiency and 27000 rpm you have almost 215 mph. A 7x10 at the same rpm and efficiency is just a hair under 180mph.

Which still leaves the original, unstated, question. Why doesn't anybody cowl the engines on their planes when they try for high speed?

For really high speed, I think it's a twin you need.

Bill

PS: You sell good planes. wr
William Robison is offline  
Reply With Quote
Old 12-02-2002, 03:09 AM
  #15  
jlong34016
Senior Member
My Feedback: (1)
 
Join Date: Apr 2002
Location: columbus, OR,
Posts: 365
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default 7x12

Sorry i cant really tell if this was sarcastic or not. But from the other thread from LANE it looks like the destroked jett 50 down to 45 with the 8.8x8.9 that goes 217 mph is the best setup so far. I have the fai nelson that i will try with the small prop but from what atomic frog has said about the 9x7 I suspect that it will not fair well. But I do like the idea of cowling and may try to get the servos buried in the wing better. Do you think the entire pipe needs enclosed? Thanks.
jlong34016 is offline  
Reply With Quote
Old 12-02-2002, 03:45 AM
  #16  
AtomicFrawg
Senior Member
Thread Starter
My Feedback: (8)
 
AtomicFrawg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, LA
Posts: 227
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

I dont sell em, I just Build em (Just Joking Rick And Dan)

From what I have tried the 8x..... did not work.
The plane is 4lbs 6 ozs
With my 8in props it would not pull the plane. It just tourqed it into the ground or would not gain speed.
The 9x6 was slow and the 9x8 was too much.
I went to 9x7 which gave me the best speed.
But everyone seems to use what works best for them.



Later
Chris
AtomicFrawg is offline  
Reply With Quote
Old 12-02-2002, 03:47 AM
  #17  
William Robison
Senior Member
My Feedback: (3)
 
Join Date: Nov 2002
Location: Mary Esther, Florida, FL
Posts: 20,205
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

jlong:

If you were addressing me, it was not meant to be sarcastic.

Regards the props. I wrote a spreadsheet model to check props and speeds, including efficiency calculations and tip speed. Tip speed is for noise considerations. Wrote it to help me carve props, but I didn't put any speed, rpm, diameter, or pitch limits in it.

For example, the 8.8x8.75 prop at 30000 rpm, and 70% efficiency
has a tip speed of 804.44 mph, and forward speed is 174.10 mph. And most of the noise would probably be from the supersonic speeds of the prop tips. Props also lose much efficiency when they go supersonic, so diameter should be chosen for the max rpm. That's why I suggested a 7" prop - it goes supersonic at 28812 rpm, with no forward speed.

Even with the sleekest airplane the frontal area is fixed, but the airflow over the surfaces can be smoothed to decrease drag. So why no engine cowlings? But I don't think cowling the pipe would add as much speed as the increased frontal area would take away.

Reach the speed of sound, with two engines, round.

Bill

PS: Anyone who wants a copy of the model, I have it in both Lotus .wk1 and Excel/2000, PM your email and I'll send whichever you wany. wr
William Robison is offline  
Reply With Quote
Old 12-02-2002, 04:15 AM
  #18  
Noflyzone
Member
 
Join Date: Jan 2002
Location: Lafayette, LA
Posts: 46
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Engine Cowlings

Bill,

The reason for no cowlings on the Whiplash is simplicity...Everyone wants to go balistic, but without the headaches. We could spend more time cowling the engines, fairing the servos, airfoiling the fins, etc...but who really cares about the couple of mph you would gain on these small airframes. The Whiplash airfoil is so thin that the Reynolds #'s are way out there from an efficiency standpoint, so the effort is really not worth it to most guys, just more complications to deal with. You are right though, the airframes would be faster with the fairings. How much, who knows. Maybe we'll try them on future versions of the Whiplash.
Thanks for the input.
Noflyzone is offline  
Reply With Quote
Old 12-02-2002, 04:37 AM
  #19  
William Robison
Senior Member
My Feedback: (3)
 
Join Date: Nov 2002
Location: Mary Esther, Florida, FL
Posts: 20,205
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

Dan, seems to me that cowling would add more than a couple of mph, remember drag going up as the square of the speed, but you people are the ones flying them, not me.

But I am firmly of the opinion that smaller diameter and higher pitch props would give you a healthy boost in speed, always with the proviso that the plane can pass successfully through the highly inefficient low speed regime getting to the speeds you want.

With a real high pitch, the takeoff's a b****

Bill
William Robison is offline  
Reply With Quote
Old 12-02-2002, 04:43 AM
  #20  
AtomicFrawg
Senior Member
Thread Starter
My Feedback: (8)
 
AtomicFrawg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, LA
Posts: 227
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default No Damage

We have tried the smaller props.
They dont pull. The Airframe is to heavy for small props.
For my Engine and whiplash Setup The 9 in prop runs the best.
For your plane you may find that something else works better.


Later
Chris
AtomicFrawg is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service