Reed Speed

mrem Fri Apr 03, 2015 6:05 am

Hi New to forum and need some help locating a speed chart to be used in Reed Speed, any and all the help I can get will be great.
mrem

Marleysky Fri Apr 03, 2015 10:19 am

mrem wrote: Hi New to forum and need some help locating a speed chart to be used in Reed Speed, any and all the help I can get will be great.
mrem

Do you like math? Go here:
https://www.coxengineforum.com/t6535-speed-calculations?highlight=Speed+calculator

I think the linc to the UK site is expired, but the rest of the info is a good place to start.
Speed-on RC Plane

OOPS, forgot to say" Welcome to the forum" !!!

JPvelo Fri Apr 03, 2015 10:23 am

mrem wrote: Hi New to forum and need some help locating a speed chart to be used in Reed Speed, any and all the help I can get will be great.
mrem

Welcome to the forum mrem!

The online calculator I was using is no longer available.
I asked on Stunthanger and got this formula:

The full derivation is:

(2 x Line Length(ft) x #Laps x 3.14159 / time (sec)) x (3600 (sec/hr) / 5280 (ft/mi))

I did the math and it works out.
What are you building for Reed speed?

Jim

mrem Fri Apr 03, 2015 3:57 pm

Hi JIM, Thank you for the info on speed timing ,I can get my grandaughter to worker it out for me. the model I am working on is a p 51 Mustang with a old Cox .o49. I have a AMA Speed chart but it does not show low enough
for my use.
mrem

JPvelo Fri Apr 03, 2015 6:09 pm

Bill Lee on Stunthanger was kind enough to post a link to an online calculator:

http://www.nclra.org/Programs/Speeds.php

Mrem,

You should post some pictures of your build here:

https://www.coxengineforum.com/t7115p320-cef-speed-contest-design-discussions

mrem Fri Apr 03, 2015 6:47 pm

I will post photos of the p51 as I go with this project , the only thing I have is the templates now. I will try to send in some photos when I complete some work on it. mrem

Oldenginerod Sat Apr 04, 2015 4:40 am

JPvelo wrote:Bill Lee on Stunthanger was kind enough to post a link to an online calculator:

http://www.nclra.org/Programs/Speeds.php

Thanks for posting that link to the calculator. It's great, and even caters for us 21st century types by having KPH lol!

JPvelo Sat Apr 04, 2015 7:07 pm

Then there's this:

Or the more simple and commonly-used formulae:

3600 divided by the one mile time.
1800 divided by the half mile time.
3600 divided by the one kilometer time.

Admittedly, my formulae are inaccurate by a factor of 0.0395%.

A one inch difference in a 60' set of lines is .139%.

mrem Sun Apr 05, 2015 11:48 am

Happy Easter to all, I checked with my son who is a speed flyer about the chart and he said the same thing to use the one on stunt hanger, or go fast enough to use the AMA chart was this a good answer?
Mrem

mrem Sun Apr 05, 2015 5:18 pm

I have a photo of a P51 that I would like to post on this forum but I need some help in doing so, could some one tell me what to do to make the post? all info will be a big help for getting me started sending photos.
mrem

Oldenginerod Sun Apr 05, 2015 5:51 pm

Posting photos can be a little confusing to the newbie, but isn't that hard once you know how. I can't find them, but there are specific threads telling you how to do it. If no-one chimes in with a thread location, I'll offer a simple explanation if you like.
Rod.

mrem Sun Apr 05, 2015 6:30 pm

I thank you for any info you can give me.
mrem

Mark Boesen Sun Apr 05, 2015 9:55 pm

for the analog guy....
I used to/still do carry this in my flight box.

mrem Mon Apr 06, 2015 7:28 am

Mark, Thank you for the speed chart I am sure it will be used a lot of times,I have all the templates and wood to build a plane for the Reed Speed event. I will start cutting soon, thank you foe the info.

mrem

crankbndr Mon Apr 06, 2015 7:36 am

mrem wrote: I thank you for any info you can give me.
mrem

Here is a link,its found in FAQ, the last step is 'cut and paste'

https://www.coxengineforum.com/t367-how-to-post-an-image-in-a-topic

mrem Mon Apr 13, 2015 8:41 am

I am looking for a glow head adaptor that will take a glow plug, and the Eng. will not loose RPM'S that will fit a Cox .049. if some one knows where I can bye one could you let me know on this forum . it will on .049 on a reed speed plane. thanks for any help.
mrem

pkrankow Mon Apr 13, 2015 9:11 am

You can get from
http://coxengines.ca/
http://www.exmodelengines.com/

however you will have to experiment with both different glow plugs for temperature and different gasket counts. The drop-in style with a head clamp offer better performance with less fuss.

Phil

mrem Mon Apr 13, 2015 11:45 am

Thanks Phil, I will check it out. mrem

mrem Wed Apr 15, 2015 6:44 pm

:I would like to thank all the great people on this forum for all the help you gave me on the Glow Head adaptor I needed to fly in reed speed for 2015 , I talked to Joey over on Stunt Hanger and he is sending me one. mrem

joey mathison Wed Apr 15, 2015 8:56 pm

Dad the Merlin 1/2 a clamp ring and plug inserts work very nice just remember to add a pile of head shims. When it needles easily and you are not blowing a plug every run you will know it is happy. We tend to over prop and over compress both are bad for engine longetivy. Let me know if it does not work for you and I will send you a Nelson head and plugs to go with it. The cox heads that get drilled out and tapped for a standard glow plug wind up with to much volume and performance will drop a lot. Joey.

joey mathison Wed Apr 15, 2015 9:01 pm

Dad the Merlin 1/2 a clamp ring and plug inserts work very nice just remember to add a pile of head shims. When it needles easily and you are not blowing a plug every run you will know it is happy. We tend to over prop and over compress both are bad for engine longetivy. Let me know if it does not work for you and I will send you a Nelson head and plugs to go with it. The cox heads that get drilled out and tapped for a standard glow plug wind up with to much volume and performance will drop a lot. Joey.

pkrankow Wed Apr 15, 2015 10:18 pm

Start with 5 gaskets with a drop-in for 25% nitro. You'll be in the ballpark. Try adding or removing one at a time and see if it improves.

Phil

mrem Mon Apr 20, 2015 6:32 pm

With the help from the good people on this forum I have a complete P51 Mustang ready to test, now the weather here in VA is the hold up but will change soon. I will send photos when we can start flying the plane.
mrem

getback Tue Apr 21, 2015 8:25 am

Cool Mrem will be awaiting pics and videos if you can , Good luck on the Maiden !!! Popcorn

mrem Tue Apr 21, 2015 5:54 pm

I am lucky enough to have a 15 year old grand daughter who can do the photos and post them for me, she is playing fast pitch soft ball fore her high school now so I must fit in some time. I will post what ever she takes .
mrem

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