Mr Cox

Congratulations on a succesful maiden, looks like a good combination of engine and plane!

It has certainly been a long and entertaining journey, starting from a handfull of lightweight plain-bearing .049 engines and ending up with a ball bearing .07 car engine with pipe and all. Is the starter axis still in place in the backplate too?

Just out of curiosity, what will happen to the other engines that didn't qualify for airworthiness...?

Pond Skipper

Thank you Kris,

Yes the 1/2A Skorch has ended with the AME Norvel .061 great combo and wont change its fast.

The Skorch II has started with the .07 and for now and will be tested with various props for speed.
Further back in the thread I showed my back plate modification and also filled in the void with a 4mm short hex head bolt. The con rod pin extension spins around the hex head bolt. Its not ideal but a fast solution to fill the void. Second pic shows the 4mm retaining nut.


I have two Picco's .052
1 Sportswerks .05
1 Fuji .05
1 CY .06
These can be used in a smaller plane project at some point all great engines but once the Vertigo showed up the power increase is unmatched by the others. The feather weight Sportwerks at 74g could be used on the 1/2A Skorch.

https://www.youtube.com/watch?v=h47Vosb0JFE Published on Oct 4, 2015

.07 CXP engine 1.14cc

Pond Skipper

This was a painful buy at 29 bucks shipped but I'm getting lazy in me old age and have been meaning to buy one since they where about 11 bucks a pop. CB Associates .049 to .80 size test stand. It will actually take a TD .020. Nice simple mount that has enough meat on its bones to hold up to testing all my larger nitro engines /118 bucks to post a pic of the completed setup.



Ran some prime thru the engine it spins up the prop with ease will have to set up the
throttle cable next and have a .15 size NV for the carb. Thinking a 6x4 for break in.

Pond Skipper

Something I wanted to try with a 16oz aluminum beer can using a refuel kit was a quick way to have a cool addition to the field box. Dish soap and a steel cleaning pad took the labeling right off with ease. The bottle actually holds over 17oz.

The pressure from the fumes keeps the thin aluminum looking good and has a good seal on top to hold back the pressure. Enough fuel for 8 flights or two outings to the flying field with the Skorch II.

combatpigg

My Feedback: (3)

That's a nice, compact container.
I use the quart sized plastic water bottles that some bicyclists use. I like their low aspect ratio.

aspeed

Like the team race guys use. They have a pump on it, and a quickfill on the tank.

MJD

My Feedback: (1)

I bought a 16oz/500ml squeezy LDPE bottle with the rubber bung and1/4" chrome spout from the LHS car department, and made a fuel tubing adapter for the end. Holds enough of one type of fuel for a day's flying on a .15, or several 1/2A's, whatever. Back home I drain it then refill for whatever I'm doing next. t's become my favored filler for Jett and Tettra tanks too.. way more control over the fill pressure.

Pond Skipper

Yes that's the idea something compact low weight to haul out to the flying site. I require myself to walk out with field box and plane about 80yds from the car. Helps to avoid potential complaints by keeping the screaming beast far enough away from other folks at the local park, associated walking paths, dog park area and parked cars.

Pond Skipper

Today I flew 3 flights enjoyed some low throttle passes and was able to land on the door step with roll outs and no flip overs. Two landings came very close to keeping the engine running one landing actually cleared enough grass to keep the engine idling. Full span ailerons a bit more tame but still feisty will have to dial down a hair more do to faster speeds today.

Adj. after full data review / two ends of the spectrum.
Last week:
5x3 / 25.47k / 183w / 27oz static / 28.47 / 81 mph (solid thrust vertical excellent and holds speed in the turns) Clearly the additional torque from the engine in its zone.
Today:
4.75x4 / 23.578k /144w /19.3oz static / 26.46k / 100.3 mph (fast speeds, thrust- best prop)
4.5x4 / 23.98k / 127w / 16.96oz static / 27.631k / 104.7 mph (less thrust speed good down wind)
Will try the 4.2x4 but I don't expect thrust will be worth the extra speed down wind.

I have ordered a batch of APC 5x5E I plan to test as is and at 4.5x5
Expect 5x5 cut down to 4.5x5 to be best speed choice anticipate the electric prop to top out at 25.7K / 122 mph. The torque of the .07 will handle a uncut 5x5 so expect 24.5k / 116 for good thrust and speed.

combatpigg

My Feedback: (3)

That's pretty cool if you can keep the engine running, landing on shortgrass....!

[Spell Check had me combine short + grass for some reason, so I caved in and obeyed]

Pond Skipper

The grass is in bad shape the hot sun has done a number on it and it's going to take some steady rain to bring it back. I walk out to a green patch to set up camp but most of the field is dirt , small rocks and straw colored flat grass.

The plane tends to just keep going n going on landings, bleeding off speed to get to crawl mode takes a bit of distance. I had to shave down the idle down quite a bit and chop throttle very early in order to do the putt putt passes low and slow.

Mr Cox

That sounds quite similar to the regular MP Jet .061, guess I need to try mine with the same props to be sure. In my notes I have written down about 21000-21100rpm on the APC 5.7x3 prop, for the BB, RC version, with stock muffler (and 10% nitro). This would then be around 0.20hp or 150W according to the APC data files.

The DG version was much stronger though, another 2krpm or so but that was with a large century, backplate pressure, no muffler etc. Plus the internal changes, so not really available anymore.

Have you ever considered a high- or mid-wing construction instead of the low wing?
Looks like you could easily belly-land a lightweight model on that field, and save on both weight and air resistance. The only time I've used a landing gear is for when I also want to use it for take-offs.

combatpigg

My Feedback: (3)

Members of the forum could start a petition that FORCES Pond Skipper to ditch the LG....!!!
There IS power in numbers, you know...........
My personal experience with parched, short grass fields is it isn't much better than belly landing in dirt.
The nastiest things to skid land into at my field are the moist "Mole Hills" and "Cow Paddies"...they will ruin your day if you didn't bring cleaning supplies. It's not as bad as crashing, but the engines can get just as packed with mud.

fizzwater2

My Feedback: (61)

Cow patties - mud?

MJD

My Feedback: (1)

Maybe he's skeert the thing will fly too fast without the LG?

combatpigg

My Feedback: (3)

I've never done a "side by side" comparison with LG and without LG, but on a 100 mph plane you could take the difference in speed and then see if any physics majors can figure out the amount of drag in ounces [or pounds].
In the 1950's Hot Rod Magazine did a similar study of cars with no fenders VS fenders, hub caps VS no Hub caps, full belly pan VS none and a handful of other comparisons to measure the amounts of drag resulted. I believe they also factored how much HP each item was worth.
I liked those early magazines, they were really educational.

Pond Skipper

Back when I was a noob in the 80's I would scratch build high wing planes not so great flying inverted but real stable.
The wing at the saddle traps air compressing more as the fuselage aids perhaps providing additional lift as its attribute.

Chuck makes a good point the engines stay cleaner if the landing gear is keeping the engine out of the various mediums,
cow poo is not an issue at my park but I do see deer, dog and rabbit offerings.
One thing to avoid is the fire ant mounds stand on them while flying will have you landing fast to do the ant dance.
Land in the ant mound and they will swarm the craft fast doing all they can to kill or run off the predator that has
destroyed their primary colony entrance.

Skeeeeerd?
Not even, thar be a 09 on the wing for a reason I will slap on a modified TD .09 with a Nelson head
at some point, has a high performance crank and a bored out polished venturi. Throttle will be with
a Medallion sleeve. I plan on using one of my micro size pressure taps to keep the tank pressure
high so the engine wont suffer in the turns and climb outs. For now though I am enjoying the
piped 07 it could really shine with the 4.5x5. I went with a bolt on landing gear for a reason.

Servo saver skid plate for more speed during plush grassy seasons good for about 6 months out
of the year. Should be good for about 6mph + on the top end and climb rate will improve.




Adj. after full data review / two ends of the spectrum.

5x3 / 25.47k / 183w / 27oz static / 28.47 / 81 mph
4.75x4 / 23.578k / 144w / 19.3oz static / 26.483k / 100.4 mph
4.5x4 / 23.98k / 127w / 16.96oz static /27.631k / 104.7 mph

Pond Skipper

In my small prop bin I found a composite 5x5E to try while I wait for the APC 5x5E's to show up.
I have many sizes in this brand the small ones are not as robust as the APC brand but may do just fine.



New high resolution photo's actual vid frames 1920x1080P

Pond Skipper

APC 5x5E props came in. I bench tested to 20,530 average steady saw up to 21.2 but felt that was pushing it heat wise.
So safe as it goes for 97.2mph / static should unload to 23.6k /112mph down wind and swan dives to 118mph. I had hoped for 120mph level down wind perhaps the thinner E airfoil will allow more top end then anticipated.

Should be a 100mph + into the wind with the static results.

Pond Skipper

double post

combatpigg

My Feedback: (3)

The 5 x 5 is one of the most popular models at San Quentin..!

Pond Skipper

Just got back from testing the APC 5x5E

2nd best pass 24,370 / 115.4 mph
1st best pass 24,942 / 118.1 mph
Not bad for a .07 engine hauling a 18.5oz plane.

Short vid as a couple walked right in my zone with their two dogs out of all the vast area to walk.
I had to back off the throttle the rest of the run isn't worth watching but did manage to get two down wind passes on vid.

https://www.youtube.com/watch?v=HW9AD3Jbp4M

combatpigg

My Feedback: (3)

Congratulations..!
It might be a pretty expensive proposition to find a better prop than that.

Pond Skipper

Very true these APC 5x5E are just $1.80 ea. I bought 4 of them for 1.99 shipping so $2.30 per to the door. The Skorch II lands well and haven't broke any of the props tried thus far.

5x3 / 25.47k / 183w / 27oz static / 28.47 / 81 mph
4.75x4 / 23.578k / 144w / 19.3oz static / 26.483k / 100.4 mph
4.5x4 / 23.98k / 127w / 16.96oz static /27.631k / 104.7mph
5x5E / 20.43k / 120w/ 16.1oz static / 24.94 / 118.1 mph


Bought two of these black carbon 4.75x4.75
If 4.4x4.75 at 26.6k / 120mph / $14.97 to the door.

Pond Skipper

Okay good news if you like small tuned pipes for .09 to .12 size engines.
This one cost me 20 bucks shipped in 4 days / 30 bucks to the door.
My contact only has 6 left up for grabs.

Pics show next to the MACS .10 to .15 pipe and up against the .05 to .06 Profi pipe.
34g as shown / Russian race pipe for 1.5cc engines.
10.25 in long.



The pipe seems better suited for the the .12
If: 5.5x4 at 28.6k static for 31.8k ish unloaded / 120 mph.
I stretch the setup to 11in with the coupler from piston face.