Cox Engines Forum
You are not logged in! Please login or register! Guests are limited to posting in the "General Questions (Guest Posting Allowed)" section only. Becoming a member is fast, easy and FREE!


Log in

I forgot my password

Search
 
 

Display results as :
 


Rechercher Advanced Search

Latest topics
» 1939 Plymouth truck.. with radial engine installed
by rsv1cox Today at 5:16 pm

» R/C dumb. Could use some help
by roddie Today at 10:59 am

» Tee Dee Head vs Medallion Head
by getback Today at 8:59 am

» Follow The World's Smallest Traveling Engine!
by getback Today at 8:34 am

» Roddie and Lynne-10 years
by MauricioB Yesterday at 2:38 pm

» Can these be used for glow power?
by coxaddict Yesterday at 5:35 am

» **VOTE-ON-THE-NEXT-COX-ENGINE-OF-THE-MONTH** (December 2017)
by coxaddict Yesterday at 5:22 am

» OS FS30 marine conversion
by 1/2A Nut Tue Dec 12, 2017 9:05 pm

» I'm Back... again
by fit90 Tue Dec 12, 2017 6:06 pm

» Hitting the nail on the head
by fredvon4 Tue Dec 12, 2017 1:05 pm

Cox Engine of The Month
December-2017
1/2A Nut's

"Chrome Moly TD .020 RC"



PAST WINNERS
Speed Contest 2018
CEF Traveling Engine

Gallery


Win This Engine!
The Traveling Prop
World of Aviation

off topic air foils

Page 1 of 2 1, 2  Next

View previous topic View next topic Go down

off topic air foils

Post  cjuliano on Mon Jan 09, 2012 8:29 pm

which airfoil creates the most lift at slow air speeds
avatar
cjuliano
Bronze Member
Bronze Member

Posts : 40
Join date : 2012-01-09
Age : 27
Location : NJ

View user profile

Back to top Go down

Re: off topic air foils

Post  nitroairplane on Tue Jan 10, 2012 1:58 am

Quite open question.
For low speeds I like flying nice under cambered wings.
avatar
nitroairplane
Top Poster
Top Poster

Posts : 6956
Join date : 2011-04-11
Location : London

View user profile http://modeldieselengines.forumstopic.com/

Back to top Go down

Re: off topic air foils

Post  cjuliano on Tue Jan 10, 2012 3:35 pm

can you show me a picture of that wing
avatar
cjuliano
Bronze Member
Bronze Member

Posts : 40
Join date : 2012-01-09
Age : 27
Location : NJ

View user profile

Back to top Go down

Re: off topic air foils

Post  nitroairplane on Tue Jan 10, 2012 3:38 pm

cjuliano wrote:can you show me a picture of that wing



there ya go.
avatar
nitroairplane
Top Poster
Top Poster

Posts : 6956
Join date : 2011-04-11
Location : London

View user profile http://modeldieselengines.forumstopic.com/

Back to top Go down

Re: off topic air foils

Post  microflitedude on Tue Jan 10, 2012 4:09 pm

nitroairplane wrote:
cjuliano wrote:can you show me a picture of that wing



there ya go.

Good stuff to memorize.
avatar
microflitedude
Top Poster
Top Poster

Trusted Seller
I Support My Forum

Posts : 3417
Join date : 2011-08-17
Age : 19
Location : Columbia, SC

View user profile https://www.facebook.com/MiniCub?fref=ts

Back to top Go down

Re: off topic air foils

Post  nitroairplane on Tue Jan 10, 2012 4:34 pm

Yes very important for the designer Smile
avatar
nitroairplane
Top Poster
Top Poster

Posts : 6956
Join date : 2011-04-11
Location : London

View user profile http://modeldieselengines.forumstopic.com/

Back to top Go down

Re: off topic air foils

Post  cjuliano on Tue Jan 10, 2012 4:43 pm

thanks
avatar
cjuliano
Bronze Member
Bronze Member

Posts : 40
Join date : 2012-01-09
Age : 27
Location : NJ

View user profile

Back to top Go down

Re: off topic air foils

Post  nitroairplane on Tue Jan 10, 2012 4:44 pm

Anytime just ask.
avatar
nitroairplane
Top Poster
Top Poster

Posts : 6956
Join date : 2011-04-11
Location : London

View user profile http://modeldieselengines.forumstopic.com/

Back to top Go down

Re: off topic air foils

Post  cjuliano on Tue Jan 10, 2012 5:24 pm

how do i post images
avatar
cjuliano
Bronze Member
Bronze Member

Posts : 40
Join date : 2012-01-09
Age : 27
Location : NJ

View user profile

Back to top Go down

Re: off topic air foils

Post  WingingIt74 on Tue Jan 10, 2012 5:27 pm

There also is a KFm airfoil. It's wild that it actually works.

_________________
-Travis

Winging It! with Travis & Jeremy
On FaceBook & YouTube
avatar
WingingIt74
Moderator

Trusted Seller
Posts : 3184
Join date : 2011-08-11
Age : 43
Location : Waterloo, IL

View user profile https://www.facebook.com/wingingit74/

Back to top Go down

Re: off topic air foils

Post  nitroairplane on Tue Jan 10, 2012 5:34 pm

WingingIt74 wrote:There also is a KFm airfoil. It's wild that it actually works.


Those are crazy I have to use them one day!
avatar
nitroairplane
Top Poster
Top Poster

Posts : 6956
Join date : 2011-04-11
Location : London

View user profile http://modeldieselengines.forumstopic.com/

Back to top Go down

Re: off topic air foils

Post  nitroairplane on Tue Jan 10, 2012 5:50 pm


Looks interesting.
You will need to sand it smoother though.
avatar
nitroairplane
Top Poster
Top Poster

Posts : 6956
Join date : 2011-04-11
Location : London

View user profile http://modeldieselengines.forumstopic.com/

Back to top Go down

Re: off topic air foils

Post  cjuliano on Tue Jan 10, 2012 5:51 pm

think it will work well
avatar
cjuliano
Bronze Member
Bronze Member

Posts : 40
Join date : 2012-01-09
Age : 27
Location : NJ

View user profile

Back to top Go down

Re: off topic air foils

Post  nitroairplane on Tue Jan 10, 2012 5:53 pm

Yes once sanded.
What is it going to be on?
avatar
nitroairplane
Top Poster
Top Poster

Posts : 6956
Join date : 2011-04-11
Location : London

View user profile http://modeldieselengines.forumstopic.com/

Back to top Go down

Re: off topic air foils

Post  cjuliano on Tue Jan 10, 2012 5:57 pm

think it will fly
a 400g plane
with a cox .049 sure start

avatar
cjuliano
Bronze Member
Bronze Member

Posts : 40
Join date : 2012-01-09
Age : 27
Location : NJ

View user profile

Back to top Go down

Re: off topic air foils

Post  cjuliano on Tue Jan 10, 2012 7:22 pm

any one
avatar
cjuliano
Bronze Member
Bronze Member

Posts : 40
Join date : 2012-01-09
Age : 27
Location : NJ

View user profile

Back to top Go down

Re: off topic air foils

Post  John Goddard on Wed Jan 11, 2012 5:00 am

I think you need to give the motor a fair bit of down thrust, it'll just keep looping otherwise.
Besta luck Very Happy
avatar
John Goddard
Diamond Member
Diamond Member

Trusted Seller
Posts : 2447
Join date : 2011-11-24
Age : 53
Location : Leyton North East London

View user profile

Back to top Go down

Re: off topic air foils

Post  andrew on Wed Jan 11, 2012 7:52 am

John Goddard wrote:I think you need to give the motor a fair bit of down thrust, it'll just keep looping otherwise.

John's made a very valid point.

If your motor is mounted as shown in the picture, the plane will be uncontrollable. Downthrust, or having the motor pointed downward relative to the angle of attack (the relative angle of the wing as the plane moves thru the air), is necessary to keep the aircraft from continually trying to climb, especially with high lift airfoils. Within a specific speed range, lift is related to the square of the velocity, so it goes up quickly as the speed increases. Before RC, freeflight planes had to be trimmed to fly on their own without pilot input. Downthrust was used as one of the trimming components. When under power and flying faster, the downthrust worked against the lift generated by the wing to keep the plane from ballooning or pitching up. It would be adjusted so the plane would fly in a slight climb. When the motor quit, the speed dropped off, as did the lift. But without the motor trying to pull the nose downward, the plane would be set up to fly in a fairly flat glide.

Downthrust is still used today on planes with lifting airfoils --- partially to compensate for lift to velocity squared relationship. When looking at your plane from the side, with the fuselage sitting as you think it will be angled in the air, the motor should be pointed slightly downward.

400g AUW is fairly light and the Surestart will haul it around quite well.

andrw
avatar
andrew
Diamond Member
Diamond Member

Posts : 1223
Join date : 2011-08-11
Age : 70
Location : Western Kentucky

View user profile http://web2.murraystate.edu/andy.batts/ps/POWERSUPPLY.HTM

Back to top Go down

Re: off topic air foils

Post  Kim on Wed Jan 11, 2012 8:11 am

[quote="nitroairplane"]
cjuliano wrote:can you show me a picture of that wing



there ya go.[/quot

YEA !!!!!! for UNDER-CAMBER!!!!-----"Like Flying with Your Brakes On!"

avatar
Kim
Top Poster
Top Poster

I Support My Forum

Posts : 5746
Join date : 2011-09-06
Location : South East Missouri

View user profile

Back to top Go down

Re: off topic air foils

Post  Kim on Wed Jan 11, 2012 8:23 am

[quote="WingingIt74"]There also is a KFm airfoil. It's wild that it actually works.

Thanks a LOT, Travis. Just what I needed....something ELSE I got to try !!!!!
avatar
Kim
Top Poster
Top Poster

I Support My Forum

Posts : 5746
Join date : 2011-09-06
Location : South East Missouri

View user profile

Back to top Go down

Re: off topic air foils

Post  WingingIt74 on Wed Jan 11, 2012 8:30 am

No problem, glad I can contribute to your madness Smile

Here is proof they work...

_________________
-Travis

Winging It! with Travis & Jeremy
On FaceBook & YouTube
avatar
WingingIt74
Moderator

Trusted Seller
Posts : 3184
Join date : 2011-08-11
Age : 43
Location : Waterloo, IL

View user profile https://www.facebook.com/wingingit74/

Back to top Go down

Re: off topic air foils

Post  Kim on Wed Jan 11, 2012 10:00 am

Cool! I'll have to check it out on the airport's WiFi.

Also, I wasn't challenging the performance claims..learned along time ago to keep my criticism to my self 'till I've got a little knowledge !

Wonder how easy this would be to apply to a slab balsa airfoil???? Looks like a little laminating and kazoom ! Off to the races !
avatar
Kim
Top Poster
Top Poster

I Support My Forum

Posts : 5746
Join date : 2011-09-06
Location : South East Missouri

View user profile

Back to top Go down

Re: off topic air foils

Post  andrew on Wed Jan 11, 2012 10:44 am

Kim wrote:Wonder how easy this would be to apply to a slab balsa airfoil???? Looks like a little laminating and kazoom ! Off to the races !

The KFm airfoils are really quite interesting. Of course, the supporters love them and the detractors say the efficiency claims are bogus. I've built several electric foamys that use the KFm1 and KFm2 foils and they do work fairly well, particularly at the slower speeds we fly.

I build using Dollar Tree Readiboard with the paper peeled off, so with a little care, the leading edges can be nicely rounded. In the attached pic, I use Scotch storage tape across the area 1-2, then roll the panel over toward the beveled side. What's left of the bevel crushes and the LE with tape is round. The "step" is usually 3/16" or 1/4" square balsa and also serves as a spar. Two pieces of foam, one balsa spar, a little glue and a strip of tape --> your done. Ta-da: you have a wing for 50 cents.

avatar
andrew
Diamond Member
Diamond Member

Posts : 1223
Join date : 2011-08-11
Age : 70
Location : Western Kentucky

View user profile http://web2.murraystate.edu/andy.batts/ps/POWERSUPPLY.HTM

Back to top Go down

Re: off topic air foils

Post  Kim on Wed Jan 11, 2012 11:24 am

andrew wrote:
Kim wrote:Wonder how easy this would be to apply to a slab balsa airfoil???? Looks like a little laminating and kazoom ! Off to the races !

The KFm airfoils are really quite interesting. Of course, the supporters love them and the detractors say the efficiency claims are bogus. I've built several electric foamys that use the KFm1 and KFm2 foils and they do work fairly well, particularly at the slower speeds we fly.

I build using Dollar Tree Readiboard with the paper peeled off, so with a little care, the leading edges can be nicely rounded. In the attached pic, I use Scotch storage tape across the area 1-2, then roll the panel over toward the beveled side. What's left of the bevel crushes and the LE with tape is round. The "step" is usually 3/16" or 1/4" square balsa and also serves as a spar. Two pieces of foam, one balsa spar, a little glue and a strip of tape --> your done. Ta-da: you have a wing for 50 cents.



Well... cool....Item # 37,320 on "Kim Lists of Projects to Try/Complete Before He Croaks" .... !!!!!!!!!!!!!!!!!
avatar
Kim
Top Poster
Top Poster

I Support My Forum

Posts : 5746
Join date : 2011-09-06
Location : South East Missouri

View user profile

Back to top Go down

Re: off topic air foils

Post  Sponsored content


Sponsored content


Back to top Go down

Page 1 of 2 1, 2  Next

View previous topic View next topic Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum