Re: Tee Dee Performance Crank

1/2A Nut Wed Nov 12, 2014 2:46 pm

Happy to help Balogh Smile

I look forward to your flight report, before launch day if you have a chance post a few pics of the plane I would like to review.

The method for fuel delivery is the same as what was used in the high wing plane in the video in regards to the TD .010 speed plane?

Cold

balogh Wed Nov 12, 2014 4:34 pm

Thanks 1/2A Nut,

here is to where my project has advanced tonight:

1. Dihedral; I finally settled at 6 degree, the 14 degree looked way too much (per my gut feeling):

Tee Dee Performance Crank - Page 4 Skorch12

2. Tail section; fuse tapering was limited as the snooker pole allowed thus the tail remained wide enough to allow the pushrods to be lead through the tail opening rather than drilling holes on the fuse skin; I like this hidden design that I have used on other planes too:

Tee Dee Performance Crank - Page 4 Skorch13

3. Other main parts (not yet glued, just thrown together for this photo session); The wing is not swept back; I added some washout to the bottom at the tip as you suggested; will strengthen the wing center by thin plywood sheets CA-d to the top and bottom; Stab, rudder and elevator parts by my gut feeling; may look small but given the expected high speed I guess these will suffice;

Tee Dee Performance Crank - Page 4 Skorch14

4. Fuel system: I will resort to my good old party-balloon design that allows wingovers, prevents fuel foaming, and makes the vent pipe unnecessary. Also fills the void behind the firewall more flexibly than a plastic tank would (btw with a heavy clunk that I do not have to use in the ballon tank)

5. Will have 3 channels; I did not want to complicate my life with ailerons; my mid-winger Toucan also runs on 3 channels and reacts/does aerobatics nicely...at least on my level. I have 2 larger R/C planes (1,6m span) powered by OS Max FS 56-s that have ailerons and those fly fantastically...but those planes are ARF-s so I did not have to mess around by cutting and sanding and rigging the ailerons..an Australopithecus should not fiddle on cloackworks, I stay with my flintstone pottery.

Will post further pics as I advance further...Chances are I wont finish by weekend..I just do not want to mess it up hasting..

1/2A Nut Wed Nov 12, 2014 7:51 pm

Yes good move with the dihedral that looks right! I moved the horizontal stab back some to give the plane more aesthetic balance but more so to add stability with a longer tail moment the blue dot in the back shows where the fuselage ends at this time.
You can further increase the tail moment by modifying the wing shape some. It appears you're a bit long in the nose. Are you going with a TD .049 if so the platform may balance out ok. You can fake a cockpit with some black will profile well in the air as an option. Also skinned back the leading edge of the horizontal stab adds a tad speed and blends with the optional wing taper.

Tee Dee Performance Crank - Page 4 Skorch10

1/2A Nut Wed Nov 12, 2014 8:02 pm

What is the wing span and cord?

Did you do 6 degs per wing pannel for perhaps 12 degs total?

balogh Thu Nov 13, 2014 1:41 am

That is correct, the halfwing length is 39,5 cm and the wingtip stands at 4,5cm height when the wing is level, i.e. the dihedral of the half wing is around 6,5 degree.

The pic on the fuse maybe delusive, I took the wing saddle position from your cutting pattern pic you posted earlier here.

The wing cord is 13cm at its widest point i.e. where the trail edge starts to taper towards the wing panel, which is a solid balso sheet 1cm thick, sanded to the airfoil.

I will use one of my TD051-s so the nose length as you said may not be a problem here.

I am hesitating whether to sand off the trail edge as you sketched, because the wing panels are already glued, and I made them identical by pressing them together and sanding the contuor before glueing the halves together. I have a tendency to mess up things at the second attempt so I would rather leave the contour as it is because at least it is simmetrical now. I assume this may add a bit of a drag and lower the speed?

1/2A Nut Thu Nov 13, 2014 3:43 am

I would leave the wing alone then if you are not comfortable the extra area will make for extra lift.

I went ahead and took down the dimensions in centimeters for your reference.

Tee Dee Performance Crank - Page 4 Skorch11

Yes the weight of the TD .051 should be good. RC Plane

Wing span is 30in / 76.2cm and cord at the center is 4in. / 10.16cm

Wing Area:
88 (square inches) = 567.7408 square centimeters

balogh Thu Nov 13, 2014 5:37 pm

Thanks for the dimensions. Looks like the nose of my plane is a bit long I. e. 11 cm so it may have the C G a bit in the front.

1/2A Nut Thu Nov 13, 2014 7:30 pm

2.74 centimeters = 1.1 inches

Yes it has me a tad worried, with small planes this is a lot. You will have to check the balance when fueled vs when empty and split the difference. Wink

Or cut the nose down silent

balogh Fri Nov 14, 2014 12:24 am

1/2A Nut wrote:2.74 centimeters = 1.1 inches

Yes it has me a tad worried, with small planes this is a lot. You will have to check the balance when fueled vs when empty and split the difference.

Or cut the nose down

Well, the nose of my Toucan of comparable dimensions is even longer, and it takes-off with 2 oz of fuel in its nose and lands with empty tank equally well balanced. (See the wing saddle cutout position on the Skorch fuse laid by the side of the Toucan)

Tee Dee Performance Crank - Page 4 Toucan10

So I hope the plastic surgery on the nose of my Skorch will not be necessary...actually that would probably mean the end of this poor plywood bird because I could certainly not glue the firewall back as strong as it is now...

In China Europeans are called long-nose...you never know, this should work here as well...I will keep you posted on the flight results, I just hope to be able to finish this Seed (Skorch Eastern European Dragster ) by Sunday.

1/2A Nut Fri Nov 14, 2014 3:52 am

Yes if you can get the CG set it will fly for sure, dynamically with the longer nose may help the plane track in the turns better.

Hehe like the SEED concept the natural low drag lines should help make this bolt along with authority. Look forward to the flight report. What size prop will you try first?
Thumbs Up

balogh Fri Nov 14, 2014 4:16 am

I have used Bernie's COX 5x4 black nylon props with very good experience lately (22,5k static and up to 26k unloaded, as you so in my vid on youtube), and still have a couple COX 3-bladed 5x3 props (that I saved as they are no longer in productuion) that fit the TeeDee049/51 output/rpm curves the best.

1/2A Nut Fri Nov 14, 2014 4:50 am

Great, the 2B 5Dx4P will do the job. Should get 70mph +
Are you going with a throttle?

I have found 3 bladed props to add a bit too much torque roll / forces one to add in more right thrust or more trim.

Surfer_kris Fri Nov 14, 2014 7:42 am

26000rpm on a 5x4 prop from a cox .049 engine sounds crazy somehow... Affraid or WOW!

(even on a 5x3 that would be pretty good numbers)

I though the power curve dropped fairly fast above 22krpm and that it was not safe for the engine above 24krpm...

Mark Boesen Fri Nov 14, 2014 1:00 pm

Hi Chris,

You're right, they don't. Back when I was racing 1/2A pylon, a Tee Dee would turn a modified Master Airscrew or a Cox Competition 5x4 (cut down to a 4.75x4 with a scimitar style tip) 22.5-23 on the ground and would really unwind in the air (plus 10%?) failure of the ball socket was a common problem if you ran it a little too lean or on a slightly smaller prop.
I think one season I went thru 3-4 new piston/sleeves, which wasn't so bad as the local hobby shop had the Tee Dee piston/cylinders in stock, I think they were like 13 bucks or something. I've never seen or heard of anybody running a Cox three blade prop, i'm sure it will turn a lot of RPM on ground, but will probably flex pretty bad in the air.

1/2A Nut Fri Nov 14, 2014 2:04 pm

Yes further back in this thread a link was posted for the Cox instruction manual stating 24k being the max rpm they didn't say on the ground or in the air just max. So we can assume anything after 24K you run the risk of failure or excessive wear to early failure. Good point on running rich allows pushing the rpm up. I run 25% castor and adjust the NV as clean as I can without going lean. Because I choose to fly RC with my engines I avoid excessive engine load do to prop size / pitch, plane weight or design drag.

balogh Fri Nov 14, 2014 7:02 pm

Surfer_kris wrote:26000rpm on a 5x4 prop from a cox .049 engine sounds crazy somehow...
(even on a 5x3 that would be pretty good numbers)

I though the power curve dropped fairly fast above 22krpm and that it was not safe for the engine above 24krpm...

I measured it with a smartphone app so the number is as crazy as the app ...BTW it measures exactly the same when the engine is on the ground i.e. 22,5k, as the Hobbyco minitach... Safe or not, this is what it tachs...with 100+hours runtime it looks like 24k is only a theoretical safety limit that my 051 does not seem to be aware of..

balogh Fri Nov 14, 2014 7:11 pm

1/2A Nut wrote:Great, the 2B 5Dx4P will do the job. Should get 70mph +
Are you going with a throttle?

I have found 3 bladed props to add a bit too much torque roll / forces one to add in more right thrust or more trim.

Voila:

Tee Dee Performance Crank - Page 4 Skorch15

Tee Dee Performance Crank - Page 4 Skorch16

Looks like I will have the maiden flight tomorrow. The hinges on the rudder and elevator are not yet glued in, neither the servos installed. I have a good 2 hours work left before I can fly it.

Too bad that only a 4,8V NiMH battery with 300mAh capacity has room in the fuselage. I will have micro-servos and wonder ho long such a battery pack will last between 2 recarges? Maybe an hour's flight?

balogh Fri Nov 14, 2014 7:17 pm

Mark Boesen wrote:Hi Chris,

You're right, they don't. Back when I was racing 1/2A pylon, a Tee Dee would turn a modified Master Airscrew or a Cox Competition 5x4 (cut down to a 4.75x4 with a scimitar style tip) 22.5-23 on the ground and would really unwind in the air (plus 10%?) failure of the ball socket was a common problem if you ran it a little too lean or on a slightly smaller prop.
I think one season I went thru 3-4 new piston/sleeves, which wasn't so bad as the local hobby shop had the Tee Dee piston/cylinders in stock, I think they were like 13 bucks or something. I've never seen or heard of anybody running a Cox three blade prop, i'm sure it will turn a lot of RPM on ground, but will probably flex pretty bad in the air.

The COX Stuka used the 3-bladed 5x3 black nylon prop...COX International sold it for some time but Bernie said a new mold would be prohibitively expensive so it is no longer sold.

The only way I can trach the COX mid-air unloaded is an acoustic tach for Samsung smartphones. Given that it measures on the ground the same as the Hobbyco minitach, even if I disregard the Doppler effect the mid-air measurement must be correct.

I have no reason to lie as to the rpm of my engine.

1/2A Nut Fri Nov 14, 2014 7:46 pm

Looking gooD!!!!!!!!!!!!

- So dowels in the fuselage for the rubber bands ?
- Elevator servo, rudder servo ( throttle servo)??
- 300mah should give you at least 5-7 flights say 6-8 minutes each depending on how much acro you fly.

If you can record a video during playback you can measure the rpm with the phone app.
Good idea on mounting the vertical stab and horizontal stab Very Happy

cox24711 Fri Nov 14, 2014 7:55 pm

1/2A Nut wrote:Looking gooD!!!!!!!!!!!!

- So dowels in the fuselage for the rubber bands ?
- Elevator servo, rudder servo ( throttle servo)??
- 300mah should give you at least 5-7 flights say 6-8 minutes each depending on how much acro you fly.

If you can record a video during playback you can measure the rpm with the phone app.
Good idea on mounting the vertical stab and horizontal stab

1/2a nut please send me the plans i want one for my thermal hopper i am soon going to be fixing i am Well i am bidding, buying parts ,making ,flying that what il need to d cos i don't have a tee dee

1/2A Nut Fri Nov 14, 2014 8:07 pm

Sanik Ni-MH 2/3AAA 1.2V 400mAh 10*30mm

http://www.ebay.com/itm/4-SANIK-iDEC...#ht_2089wt_998

Tee Dee Performance Crank - Page 4 Sanik_10

Surfer_kris Sat Nov 15, 2014 12:39 am

balogh wrote:
I measured it with a smartphone app so the number is as crazy as the app ...BTW it measures exactly the same when the engine is on the ground i.e. 22,5k, as the Hobbyco minitach...

Are you sure it is a 5x4 prop? Perhaps the pitch is off or something...
If not you would easily win the tachrace with that engine. Wink

balogh Sat Nov 15, 2014 9:33 am

Surfer_kris wrote:
balogh wrote:
I measured it with a smartphone app so the number is as crazy as the app ...BTW it measures exactly the same when the engine is on the ground i.e. 22,5k, as the Hobbyco minitach...

Are you sure it is a 5x4 prop? Perhaps the pitch is off or something...
If not you would easily win the tachrace with that engine.

Yes this is Bernie's genuine 5x4 black nylon COX prop...I may run for the tachrace if I understand how to apply...should one send his engine to the tester in the USA?

balogh Sat Nov 15, 2014 9:45 am

1/2A Nut wrote:Looking gooD!!!!!!!!!!!!

- So dowels in the fuselage for the rubber bands ?
- Elevator servo, rudder servo ( throttle servo)??
- 300mah should give you at least 5-7 flights say 6-8 minutes each depending on how much acro you fly.

If you can record a video during playback you can measure the rpm with the phone app.
Good idea on mounting the vertical stab and horizontal stab

How about these ones?

Tee Dee Performance Crank - Page 4 Seed_110

Tee Dee Performance Crank - Page 4 Seed_210

I seem to have finished the plane. Yes, 3channels including the throttle for the TEEDEE 050 that I mounted on this one. I tached it and revs only 17,5k which is a tad worse than what the Manual says. or what I know the 050 is up to: 18k or in the neighborhood..For some reason it gets overheated even with 5 shims under the head and only 20% nitro.

I could not give the SEED the maiden flight today as it is getting dark pretty early (same timezone as Paris but 1300km eastward from France....) and instead I set the idle on the 050.
For the initial runs I will use this engine as I do not know how the plane reacts and chances to smash it are lower with the 050 than with a naked 051/049 than spins the 5x4 prop at 22,5 by default.

I will add an exhaust throttle barrel to the naked as well.

Tomorrow I will know more

balogh Sat Nov 15, 2014 9:52 am

And once again, many thanks to you 1/2A Nut for the remote help and advice to build this one.

With the less tapered fuselage and only moderate airfoiling the balsa wing that is also wider than yours, it weighs 13 oz with the tank empty. Just a bit lighter than my Tuocan that flies around 70km/h, but this one is slimmer with less drag...looking forward to seeing it fly tomorrow, weather permitting..

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