Canard Community Forum  

Go Back   Canard Community Forum > Firewall Backward and Forward > Propellors
FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
  #1  
Old 05-23-2004, 11:47 AM
tnt's Avatar
tnt tnt is offline
Member
 
Join Date: Apr 2004
Location: Denver Colorado
Posts: 1,202
Default Rotary-PRSU-Props

Last night I sent a email to Klaus of Lightspeed to see what propeller solution Lightspeed might have for the combination of Renesis & Tracy Cook 2.85:1 redrive.

Tracy says this redrive on a Renesis should have a minimum prop diameter of 74inches. No good for the Cozy as it has a max prop diameter of 70" (and no I wouldn't stretch the legs or lift its fanny). I think and hope there are other things about the propeller that could be played with.

I haven't seen prices for Lightspeed props but I like his description of construction and engineering reputation.
Reply With Quote
  #2  
Old 05-23-2004, 12:06 PM
Dust's Avatar
Dust Dust is offline
Super Moderator
 
Join Date: Apr 2004
Location: Troy, Michigan
Posts: 7,963
Default

Where did you get the max prop diameter? And have you done the math to see at what angle you would have to land at to kiss it?
__________________
Enjoy the build,njut av byggandet, godere il costruire, nyd bygningen, geniesse den Bau, apolafse tin kataskevi, disfrute la construcción, curta a construção, Pidä hauskaa rakentamisen parissa, bouw lekker,uživaj grade?inaslajdaites postroikoi, geniet die bou
dust

maker of wood, fiberglass, foam dust, metal bits and one day a Cozy will pop out and swiftly whisk me from meeting old friends and family to adventures throughout the world
Reply With Quote
  #3  
Old 05-23-2004, 12:08 PM
tnt's Avatar
tnt tnt is offline
Member
 
Join Date: Apr 2004
Location: Denver Colorado
Posts: 1,202
Default

Oops, maybe that max prop diameter I have scribbled on this paper didn't come from the handbook. Nice, I can't find my handbook just now, is the max Cozy prop diameter larger?

I'm leaving the math to those that can do it but I always have in mind that max pitch angle on the ground.
Reply With Quote
  #4  
Old 05-23-2004, 12:17 PM
Dust's Avatar
Dust Dust is offline
Super Moderator
 
Join Date: Apr 2004
Location: Troy, Michigan
Posts: 7,963
Default

Exactly, and you might be surprised at the size prop that will be OK on the Cozy, except maybe with a 25 degree angle landing, don't know the answer, just have the question
__________________
Enjoy the build,njut av byggandet, godere il costruire, nyd bygningen, geniesse den Bau, apolafse tin kataskevi, disfrute la construcción, curta a construção, Pidä hauskaa rakentamisen parissa, bouw lekker,uživaj grade?inaslajdaites postroikoi, geniet die bou
dust

maker of wood, fiberglass, foam dust, metal bits and one day a Cozy will pop out and swiftly whisk me from meeting old friends and family to adventures throughout the world
Reply With Quote
  #5  
Old 05-23-2004, 12:20 PM
tnt's Avatar
tnt tnt is offline
Member
 
Join Date: Apr 2004
Location: Denver Colorado
Posts: 1,202
Default

Here it is, 70" max marked on the 3-profile view. As far as 'could I still get away with a 74" prop?', I'll just accept 70" as my maximum and not think about it (unless Nat amended 70 elsewhere).
Reply With Quote
  #6  
Old 05-23-2004, 01:23 PM
Eccentric's Avatar
Eccentric Eccentric is offline
Over 650 rotary hours
 
Join Date: May 2004
Location: McMinnville Oregon USA
Posts: 66
Default

I just designed a 70" diameter, 82" pitch prop for Bulent. He is building it now. I think his is reverse rotation 2.17. If you have 2.85, you will probably still be turning a slower prop RPM than Bulent even with the Renesis engine. So you would probably need a slightly different design, with normal rotation.
Reply With Quote
  #7  
Old 05-23-2004, 06:25 PM
Dust's Avatar
Dust Dust is offline
Super Moderator
 
Join Date: Apr 2004
Location: Troy, Michigan
Posts: 7,963
Default

I think it also depends on what length prop extension you hang on the back of the plane
__________________
Enjoy the build,njut av byggandet, godere il costruire, nyd bygningen, geniesse den Bau, apolafse tin kataskevi, disfrute la construcción, curta a construção, Pidä hauskaa rakentamisen parissa, bouw lekker,uživaj grade?inaslajdaites postroikoi, geniet die bou
dust

maker of wood, fiberglass, foam dust, metal bits and one day a Cozy will pop out and swiftly whisk me from meeting old friends and family to adventures throughout the world
Reply With Quote
  #8  
Old 05-23-2004, 06:31 PM
tnt's Avatar
tnt tnt is offline
Member
 
Join Date: Apr 2004
Location: Denver Colorado
Posts: 1,202
Default

Yes Ecc, I was thinking perhaps broader blades.

Very good point Dust that I hadn't considered. I was assuming the standard commercially available motor mount and Tracy's redrive with no length modifications. In any case, I'll want to check to see where this puts the prop relative to the 'standard' motor installation and extension.

Last edited by tnt : 05-23-2004 at 06:55 PM.
Reply With Quote
  #9  
Old 05-24-2004, 12:16 AM
tnt's Avatar
tnt tnt is offline
Member
 
Join Date: Apr 2004
Location: Denver Colorado
Posts: 1,202
Default

Klaus replied. He no longer makes propellers.
Reply With Quote
  #10  
Old 06-06-2004, 02:07 PM
JungleJet's Avatar
JungleJet JungleJet is offline
start spring '05
 
Join Date: Apr 2004
Location: Denver, CO
Posts: 13
Default 72" prop

TNT,

Infinity's literature claims that you could use a 72" prop w/ retracts.
Just a thought...

scott
Reply With Quote
  #11  
Old 06-06-2004, 04:23 PM
tnt's Avatar
tnt tnt is offline
Member
 
Join Date: Apr 2004
Location: Denver Colorado
Posts: 1,202
Default

That's an invitation to enter the Infinity brawl. I'll see you on the other thread. Infinity's claim is based on having longer legs. Since you can't launch a canard with a nose-low attitude, you'll also have to lengthen the nose gear and stretch the nose-gear retract slot and reposition one end or the other of that slot.

I'm sure there's things you could do to a prop the get the full power out of the rotary-prsu-prop that cost less than that $8+. If I find an extra $8k, I'll put it into a really great prop, or an EFIS, paint-job, trip to Europe or South Africa, real-estate, ski-season condo in Telluride, better cuts of meat for a year, a camping trailer, buy a top-of-the-line RC helicopter setup and compete nationally, some BlingBling, a large flat HighDef TV, or down payment on a Mazda RX-8. If I'm forced to use longer legs it'll be the sweet simplicity and pleasurable ride of spring gear (and send Infinity a photo of my other choice)

Last edited by tnt : 06-06-2004 at 07:44 PM.
Reply With Quote
  #12  
Old 06-06-2004, 10:56 PM
LargePrime's Avatar
LargePrime LargePrime is offline
redesigning every part before build
 
Join Date: Apr 2004
Posts: 502
Default

I spoke to Jack Williamson about longer nose gear
eznoselift.com

He said raising the nose is not really a problem. The typical lift is not fully extended so you could get 4+ more inches just by letting the lift go more vertical, from the 30deg angle it is typicaly at. No changes at all

If you need to go even higher ,He said it would not be a big deal to get him to change a part. He said you could mount the lift a little further forward and there would be no differance in the install

Why would you not consider raising the cozy?
Reply With Quote
  #13  
Old 06-07-2004, 08:17 AM
tnt's Avatar
tnt tnt is offline
Member
 
Join Date: Apr 2004
Location: Denver Colorado
Posts: 1,202
Default

Quote:
Originally Posted by LargePrime
I spoke to Jack Williamson about longer nose gear
eznoselift.com

He said raising the nose is not really a problem. The typical lift is not fully extended so you could get 4+ more inches just by letting the lift go more vertical, from the 30deg angle it is typicaly at. No changes at all

If you need to go even higher ,He said it would not be a big deal to get him to change a part. He said you could mount the lift a little further forward and there would be no differance in the install

Why would you not consider raising the cozy?

That's interesting. But I have no idea whether extending the lift position is practical based on what ride you get out of it now or after lowering it further. I can see there would be a limit to how far you would want to take it toward the vertical.

As for as raising the CG when it sitting on the ground, I wasn't thinking that amount of height increase would cause a problem but 'I have no data on that'.

My issues was primarily with the chain of mods needed to the nose-gear to match the increased height of the mains.

Tom
Reply With Quote
  #14  
Old 06-17-2004, 02:38 PM
tnt's Avatar
tnt tnt is offline
Member
 
Join Date: Apr 2004
Location: Denver Colorado
Posts: 1,202
Default Stock tranny for redrive

Quote:
Originally Posted by John Slade
Oh - and while we're talking about using stock parts - I had a call from George Graham the other day. He now has 80,000 miles (he measures his flights that way for some reason) on his 2nd gear stock transmission redrive. It's a fairly low power application in a modified rotary LongEz, but still - interesting what you can do if you set you're mind to it.
Yes, that sounds like a reasonable reduction solution to this 'not a motor guy' mind. Engineered, tested and manufactured by a major corporation applying all it's resources and unnecessary parts stripped. Any idea what the reduction ratio is? I wonder if the older tranny's would fit the Renesis.

Seems like Tracy has a good one too, but if I could save a chunk of $ on the used tranny...

Last edited by tnt : 06-17-2004 at 03:13 PM.
Reply With Quote
  #15  
Old 06-17-2004, 03:32 PM
Clutch Cargo's Avatar
Clutch Cargo Clutch Cargo is offline
w/ Spinner and Paddlefoot
 
Join Date: May 2004
Location: Cape Coral, FL
Posts: 602
Thumbs up getting high

"Take me to your ladder, I'll see your leader later" (quote from astronaut landing on strange new planet with very tall beautiful women when asked if he wanted to be taken to their leader)

Yes, jacking up the Cozy (making it a misquito-zy) makes for some interesting boarding problems. I wonder if you can put internal fuel cells on a gimball?

At least bring a milk crate....no sense in diving into the cockpit, unless you're Indiana Jones

hmmmmm. could Dust be right again? naw!
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 07:03 AM.


Powered by vBulletin® Version 3.6.7
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.