Pond Skipper

Alan I had a SPAD design once would be fun to do another at some point much faster build.
I did a search on the XLS .15 one reported 21.7k with a MACS pipe and APC 7x4
Pitch is bit low I think for this engine a 5 or 6 would be better for speed. No one had
anything bad to say about the engine it seemed to be well liked with no issues, the norm
seemed to be the MAS 8x4 for sport flying acro for thrust. Alan I hope you have
your big move done soon its been going on for a while spring will be here before ya
know it..

Hey Guys MEEEERRRRRRRRY CHRISTMAS ho hO ho, I hope everyone enjoys the holidays!!

combatpigg

My Feedback: (3)

Merry Xmas..!

Pond Skipper

I picked up a rare or at least rare to buy a new unused Tarno carb for the Cox TD .09
Doing some research folks using them back in the day found the carb to idle down the
engine well and even better if you used a Tatone EM-9 muffler.

So did a break in test and during that time ramped it up once to see what sort of
power I was getting at that stage with the muffler and additional 4" tube extension
for noise control:
Update:
APC 6.3x4 Combat Prop / 20% Nitro / 16,300 / .19 hp / 142w / 24oz thrust



My guess about 16k ish if just the muffler. Open exhaust perhaps 16.5k ish.
Conclusion smaller prop if I want to unload to 20k. Perhaps the thin blade
APC 4.75 x 5.5E or the 5.25 x 6.25E with open exhaust might be the ticket.

Additionally this engine has the high performance light weight RC crank the
turbo plug head and an aluminum carb body.. The Tatone muffler has
a restriction baffle which could be drilled out to increase rpm at the expense
of a lower idle. Test was done with the same fuel. 20% nitro. More testing
to come still breaking in the engine to insure the ball socket doesn't get
stressed I do have a reset tool but want to only reset once finished with
all testing.



Note as shown: AP.09 / 165.5g vs the Cox .09 / 109.6g


Bare in mind the previous test with the rear exhaust AP .09

AP .09 Hornet - static 20% nitro

APC 5.25x6.25E / 16,715 (saito muffler optimized) 99mph
13.6oz thrust / est. unloaded 114mph / with tuned pipe should hit 120+

APC 6.3x4 / 17,610..........(saito muffler optimized) 67mph - great thrust!
MA 5.5x4.5 / 19,730........(saito muffler optimized) 84mph

aspeed

I found the AP a bit quicker than the TD as well. I used a 7-4, but with fairly similar numbers

Pond Skipper

Yes I have your data jotted down on the previous page.
Next will test without the 4" pipe extension and the E props. If need be then test
without the baffle if the results are still not getting enough increase in rpm. The
Tarno folks claim 3500 rpm with a Cox 7x4 and stress the need to use the
Cox muffler. I imagine the common round one (I have one) but a bored out
Tatone muffler should still give reasonable idle perhaps 5k with a 7x4.
I also have a few Cox RC .09's with there mufflers but they weigh more than
the Tatone muffler. Shown is the lightest set up on hand with a muffler if
bored out will breath more than the others providing good directional blast
of the good ole goo.

aspeed

I was reading somewhere that a slant cut on the outlet of a muffler makes it seem quieter. Maybe with a bigger outlet and the slanted cut, it will end up with the same noise overall? The little motors are not that loud really, but kind of irritating to some. I personally think it is better than the BRAAAP of the monster motors, but I think I am a minority. I am not sure I will be able to test my motors as much as before, as the new house in in civilization now. I can go down the 70 ft. hill to the lake , and it will be ok, but I have to drag the test stand and toolbox up the hill again, and it is pretty steep, about 20 degrees. I think I have the round muffler for the TD .09 too but have not run it that way because it is missing a washer or something.

Pond Skipper

Check out this kids new present from Christmas / scratch built gas powered boat.

https://www.youtube.com/watch?v=yUitTtbzAB4

aspeed

I made a little boat out of a sheet of 1/4" plywood just for picking up model planes and boats out of the pond. (about an 80 acre pond) Looks pretty much like that one. It was a bit spooky when there was even a bit of wind. I still have it. Now I am on Lake Erie, but even a calm day would be too much for that little thing. I think it is about 6 1/2 ft long and 3 feet wide. Got lots of weedwacker motors that would look cool on it though.

Pond Skipper

The hull is reduced from a mini jet boat that is popular to build out of aluminum typically 8 to 11ft range
I saw a two seater 10ft with 135hp engine jet drive hauling two men at 58 mph. Back in the day when I
was 19 I built a ply 7ft flat bottom boat with a 30cc engine submerged drive it did pretty good about
9mph at full throttle with just me in it. Prop was a 3 bladed nylon aircraft prop cut down to 4x6.

Pond Skipper

GPS Speed Logger came in this one is only 22.5g as shown.
Will take it down the road in the car to test the reading keeping
to a noted max speed then compare. Components side of the
board fits inside with the fuel tank leaving no bulk hanging in
the breeze.

Pond Skipper

http://www.ebay.com/itm/371344378093...%3AMEBIDX%3AIT

Bought two of these can recommend 2000mL or 1/2 Gallon seals very well zero nitro loss
large round lip with thick rubber seal. Great for storage over the winter months etc.
I have a smaller one for the field on order holds 1000mL or 1 quart. Today I'm going
flying and for now will use a full 8oz large fuel bulb allows 4 flights with the Skorch II.

combatpigg

My Feedback: (3)

A stainless container is a great thing to keep in your car to store items that you would never want to be without if you got stranded, hurt, delayed, etc.

Pond Skipper

At last data

60deg day cloudy wet field 6 to 10 mph breeze.

- tried pressure one way valve caused engine to go rich after a bit of flying
- thought maybe cold weather was cooling the pipe and causing engine to go rich
- removed one way valve engine settled down was happy didnt surge like it did during hot weather
- used on board camera see pics high speed pass blurry VS slow and low better focus
- need better rubber padding under the camera
- air flow from prop was distorting sound readings will need to use a wind dam over mic hole
- GPS speed data logger tried out and it works!!!! See field pic after 3rd run of the day.

Tested APC 4.75x5.5 (engine rpm is better with the carbon 4.75x4.75 but has fuel surges)
GPS Best Max read 172 Kmh / 107mph(kept it level no diving steady pattern passes)
- In the hand 21,560 rpm / 112.3 mph
- Best pass 23,605 rpm / 122.94 mph in theory camera and gps drag slowed the plane down to 107 mph
- If no cam no gps I would imagine more like 114mph ish, (see pic of my set up at launch)
Total on board weight less rubber bands for the camera 33.1g

Next outing will try to improve on board video vibrations and audio prop blast / was neat to see the flying field and me
Also want to get readings without the cam as it really sticks out on the air frame low weight at 10.7g with safety wire.

I took the hatch off rapped tape around the GPS logger and hatch simple solution.
Oil spray was not an issue under the fuselage but was collecting on the cam from the carb.
May relocate the cam under the plane for better viewing as well. Today I just had the cam
aimed off to the right a hair.






Older data from past runs:
5x3 / 25.47k static / 28.47k
4.75x4 / 23.58k static / 26.48k
4.5x4 / 23.98k static /27.63k
5x5E / 20.43k static / 24.94k
4.75x4.75EC / 22.86k static / 26.64k
4.75x5.5 / 21.56k static / 23.6k

combatpigg

My Feedback: (3)

The camera did pretty well considering no padding. They must have a built in damper of some kind.
I want to see if there is any rpm difference between upwind and downwind. I think the wind has energy that can be fed into the prop under the right conditions. During this time, the engine is acting like a speed brake but could be coaxed to unload a bit more.
From now on, The GPS becomes part of your side view design..!

Pond Skipper

I had some cheap grade foam under the cam only good enough to keep it in place, will use dense foam rubber next.
Easy access to the GPS is a plus, I could tuck it in with the fuel tank to get it out of the air stream with a little mod
to the tank. Needs heating it up on one edge to induce a flat spot up front around a 1/8th inch or so.

Sunday was more so a chance to test out the new gear and see how much effort would be needed to initiate them.
Turns out to be quick and trouble free. I too am curious about the prop rpm upwind / down wind, bummer the noise
was simply too much to determine clearly. I have a few ideas on better cam setup such as anti-jello vibration isolation.

combatpigg

My Feedback: (3)

What sort of plane / prop combo would be the most likely to exhibit a downwind rpm boost...?
A fat airfoil..?
A piped engine or open exhaust..?
A 4.75 x 4.75 on your .09 engine, or a 6 x 4...?

Pond Skipper

The TD .09 can handle the 4.75x5.5 the .07 is doing ok with it but the rpm
is not high enough to work with the pipe like the 4.75x4.75 can.

APC 4.75x4.75EC
- Static 22,286 rpm
- Best pass 26,640 rpm / 119.84 mph

APC 4.75x5.5E
- Static 21,560 rpm
- Best pass 23,605 rpm / 122.94 mph / Drag with GPS / Cam 107mph
- Without the additional weight and drag rpm should hit 24k / 125mph / actual will improve.

APC 5x5E
- Static 20.43k rpm
- Best pass 24.9k / 118 mph


Tally of the results shows I need to try a 4.75x5
Prop dia. must be kept the bird is big the .07 is working hard the wing span needs a TD .09
The .07 has done well but is reaching its best leaving me to settle or move up in displacement.

Love the engine pipe combo knowing it's power could set it up for a perfect match up
with an all balsa competition class "Quickie 100" - being smaller lighter should hold a steady 120.

Leaves me looking at the TD .09 open exhaust goo maker uggg. its weight is suitable.
5.25 x 6.25E open exhaust if at 23.6k unloaded / 140 mph
May require open venturi / throttle sleeve to get there engine would be pushed to its ball socket brink.
I cant open exhaust test at home it will have to be taken to the field and fired up and tach tested.
I need to see it reach 20.5k static to consider the engine.


I don't think a fat airfoil is worth using in speed applications other than for low aspect designs.
They are hard to monitor in the air (less to see) traditionally found not to be as optimum.

For a down wind boost the plane must require at least a 1.3:1 thrust ratio
With a tuned pipe the down wind assistance may improve the pipe boost with better rpm / sync

Pond Skipper

This pipe came in all the way from Ivano-frankivsk Ukraine today
bought for the ASP .12

He has 3 left: I polished mine up

http://www.ebay.com/itm/Vintage-ussr...3D321822091637




Previous results with the MACS pipe had me thinking the pipe volume
is a bit much for the displacement idle was fantastic top end lacked the
static rpm I was expecting closer to 20K


The pipe is set up at 11" allowing a sweet spot of 22.8k to 23.8 unloaded. The
engine should hold up to this rpm will test and post a vid.


Previous test:
Published on Nov 29, 2015
4th test 3.75" header rpm still in good range 20% nitro 20% oil
APC 6.5x5 / 18,980rpm / 90mph /.44hp / 1.85lbs thrust /est unloaded 115 mph.

Pond Skipper

He has 3 left: I polished mine up

http://www.ebay.com/itm/Vintage-ussr...3D321822091637

Compared to the MACS pipe


28g as shown

Pond Skipper

Tested the pipe

20% nitro and oil

MAS 5.5 x 4.5
Static 22,430 / 96 mph / .32 hp / 231w / 1.3 lbs / 21oz thrust
Header pipe was cut for unloaded rpm should jump up est 26k / 112 mph






ASP .12A MACS 1.5cc to 2.5cc Tuned Pipe
2.11cc engine.

1st test 6.25" header uncut - didn't allow full throttle - rpm / timing off.
At 60% throttle - got on the pipe well and made good power off pipe past that.
APC 6.3x4 20,700rpm. / .41hp / 78mph / 1.82lbs / 306w.

Update APC 6.3x4 with header cut to 3.75" full throttle was possible 20,030 rpm.
Est. 3.25" would be best for this prop up to 21k ish static. Unloaded est. 23.2k / 88mph.


2nd test 3.75" header - rpm range suitable for full throttle
APC 7x5 17,118 rpm / .433hp / 313w / 81mph / 2.lbs

3rd test 3.75" header - rpm range good and optimized for unloaded state
APC 7x6 / 15,830 / 90 mph / 1.75lbs thrust / .41hp / 307w / unloaded est. 103 mph+
This prop would be great mix of static thrust and speed

4th test 3.75" header rpm still in good range
APC 6.5x5 / 18,980rpm / 90mph /.44hp / 1.85lbs thrust /est unloaded 105 mph.
Prop shape should unload better than a sport prop. Best Prop Tested!

aspeed

The pipe is designed for 25,000 rpm from what I was told. If you are adding over 3 inches, I would think it would be happiest about 22,000. On the ground, I think it maybe should not be quite on the pipe, so it unloads in the air, and then gets on. Otherwise the pipe will hold you back on the smaller/lighter load props. Just thinking out loud here. I would be shortening the pipe or header a bit if you want the revs up over 22,000. Not that it is needed for the ASP materials. The 6.5 - 5 and 7-5 may hit the pipe while in the air and surprise you? maybe.

Pond Skipper

Engine has around 160 deg. timing . I cut the header down before the test to work with the unloaded rpm . 1675 × 160 ÷ 10.5 = 25.52K. The thin light MAS 5.5 x 4.5 should help keep the engine parts from being too taxed

Mr Cox

I'm not sure what you are after here. There is a lot of different numbers and some random trial and error with pipes and props...?

The stock timing on my two ASP .12 engines are around 150° only. They seem to vary a little with the machining of the liner, one is not particularly straight...

In the stock form I have not seen any gain from a pipe over an open exhaust.
The better engine, of my two ones, will spin an APC 7x4 prop at around 17000rpm with the stock muffler and 10% nitro. That is then about 0.325hp (or 242W), so the data with the MAS 5.5x4.5 then seems to indicate that there is no gain at all from the pipe (over a regular muffler) and/or perhaps the maximum in the power curve has been past...?

The same pipe works well when attached directly at the outlet of a picco .12, it then spins an APC 7x4 at around 22000rpm (compared to about 19000rpm on a tuned MVVS muffler). To me the ASP .12 in stock form is not well suited for any tuned pipe, it is simply to timid in the timing. Perhaps you could convert a car engine instead.

Pond Skipper

Tested:
I have a MAS 7x6 / I straight cut it to 5.22 x 6

Best peak 19.4k static /110.2 mph / 180w / safe static rpm
est. at 22.3k unloaded / 127mph

This is looking good so will take the time to prep the tips and
trailing edge to improve rpm to 131 mph without taking away from the dia.

Tested
APC 5.25 x 6.25E
Static 18,873 / 112 mph / 16oz thrust / 170w
If unloaded at 21.9k / 130 mph

Mr Cox

Those are rather disappointing values in terms of power...

I suggest running the engine on the same props with open face, or a regular muffler, first to have something to compare with.

On my engines I have added an extra head shim (about 0.1 mm) in order to work well on 10% nitro. So perhaps the stock compression ratio is too high for your fuel too.