"1/2 A" & "1/8 A" airplanes These are the small ones...more popular now than ever.

MDS F2A 2.5cc

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Old 01-24-2015, 05:25 PM
  #26  
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36,498 rpm best reading faded down from there at the end just under 34k..using a audio phone app.

Any idea of the rpm on your end?
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Old 01-24-2015, 06:29 PM
  #27  
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How much mph would cowl and shroud the motor / tank?
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Old 01-25-2015, 12:01 AM
  #28  
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I doubt it's doing over 30k, the prop used that day was a Graupner grey super nylon 6" x 5" cut down to 5 1/4",
I'm sure more propellor work could add another 15 - 20 kph, and cowling in the motor/tank the same again.

The idea for it came from Alex Valishev, here, http://www.f2aspeed.org/node/17

Here's a plan I drew,


[ATTACH]2067506[/IMG]
Attached Files
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Old 01-25-2015, 07:52 AM
  #29  
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I was getting another set of readings these range from 27,372 to 28,194 in lieu of a 5.25 x 5 prop
129.6 to 133.49 average 131.545 x 10% loss 13.1545 for 118.39 mph / 190.530236 kilometers per hour

He reported 117 kph on page 1

Using my method and some known data I can use my app and pitch speed calc. to get within a few mph / kph.

Last edited by Pond Skipper; 01-25-2015 at 11:04 AM.
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Old 01-25-2015, 08:15 AM
  #30  
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That might be pitch speed, but there is no reason to suspect the aircraft was actually going that speed, although they indicate that it could with sufficient power and low enough drag. Those rpm readings are reasonable. And measured prop pitch will mislead you, unless the airfoil is a flat blade, no camber, the true pitch is higher anyways.


Oh crap - looks like I spun the big end bushing. I know they need clearance but I should have done a better job checking. I have a Conquest billet rod, not the early cast rod, that may work.
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Old 01-25-2015, 10:44 AM
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Hi, I live in Helsinki/Finland.. That`s 150 kilometres to St Petersburg. We have , over the years had hundreds russian /soviet engines carried over here, especially after the fall of Soviet CCCP state. The engine in question is a product of "Sovied army aero club" produced in THOUSANDS. In Soviet time these were distribute from the central organization all over the russian state to various youth clubs. Every young member could get one if he wanted. In Baltic countries, especially guys have them lying around by hundreds, because they could, via various conections, get in their hands "real stuff" that means Rossis, Novarossis, Irvine 15 etc. There is really NO COMPARISON to them and the. MDS
A hot tip is that both this engine and the TRAXXAS 15 car engine are almost carbon copies internally to Rossi mark II. You can get very good P/C , rod and various other parts just to ordering them from your hobby shop. Just take the parts of MDS with you and measure you have the right version of Traxxas 15. But still, I just bid 2ea NOVAROSSI 15 Aero Speed engines in Ebay for F2A treiner use for about 150 dollar total (less hipping) I would use the MDS spinner assy, the pipe and the pipe silicon joint ring and simply toss everything else. Just not worth trying to figure it out, The crank is very badly finished, also tempering absolutely too soft-wears out fast. Most of the bearings rough, rodsimply too soft material, will break... The compression is way off, you have to machine the head to make the engine run near it`s pek. On top of everything, the timing is very high resonane timing so you end up having reasonable power in the region of 25.000- 35.000 rpm. Are you really going to have an engine/model combo in this rpm region and how are you planning to gt there without whiping the model very hard ? Toss it an use whatever else. ...
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Old 01-25-2015, 01:33 PM
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Hi Raddaddy - I bet a lot of the readers here wanted to know more about the history: I knew it was a situation like that, but no details. Really appreciate the info, plus the tip on the Traxxas engine.. very interesting, thanks!

My limited knowledge of MDS engines came from working with a friend of mine who imported hobby goods from Ukraine regularly, and importing some .40, .61 sport engines and FIRE 10cc. None of these, although we probably could have.

I understand what the engine does and how to use it in the air. I like RC models with snotty piped engines. If flown on a clean airframe in the 200-250 sq in wing area or thereabout (think 1/2A-1cc pylon racer size), it will have no trouble unloading and staging on the pipe in the air as long as a suitable prop is used. Same props as for CL trainer are suitable for sport speed models. I plan to prop it for 28-30,000 rpm or so, if I get that far, and I will use inflight mixture control because it is easy & not much space needed.

The Profi F2A RC .15 model I am building this winter will use one blade 3x6 - 3x7 props. It too will have in flight mixture control and with the light weight and 217 sq in wing, it will climb out fine on the engine four-cycling at 21-22k, more than enough power. I can then enter a shallow dive and adjust the mixture if needed to the unloaded mixture healthy. Then when I get scared I can shut it down and glide home.

If I had posted this on the Extreme Speed forum nobody would have questioned the sanity of using the MDS .15 on an RC model, but around here there is a considerably higher percentage of rational thought.
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Old 01-25-2015, 09:32 PM
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H MJD:
Thanks for the additional info, you are absolutely on the right track ! Small "pylon like speedsters" are PEERFECT enviroment for a "better" MDS. The fact I tried to warn and point out is: The huge majority of those speed/resonanze contest type engines that the central organization produced had absolutely NO quality control. If you look at the serial number of your engine.. several hundred thousand ! The point was that it was just "raw material" for a working engine ! The young guys would go to the lathe and fabricate themselves something that would work ! No wonder there were so many different custom engines,and producers of such. When the skills were not enough for such work, the "free" engines ended in a vault and now pop up in Ebay, etc. When the Ukrainan factory started to export the MDS and especially the English importer forced some pre check on the ones they would pay and not send back, definitely usable MDS engines could be bought here in Europe. To say the truth, some of the mas produced Russian engines.AME-VAE etc. are of really good quality, especially since the russkis adopted state of the art production technologies such as CERAMIC plated Aluminum sleeves. One day, when their designs meet the western standards ( novarossi/Picco/CMB/ Nelson etc.) we are into a new revolution in model engine technology, provided, their appetite to sky high pricing (Profi, Kostin, Cyclon etc.) would not spoil the fun...
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Old 01-25-2015, 11:52 PM
  #34  
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Welcome to the forum RadDaddy..!
It is really interesting to read about the history of East European engines. I've only heard "second hand" stories about the Soviet Union's model aviation program and their government funded hobby / recreation facilities. They took FAI competition pretty seriously and I heard that the most talented flyers, mechanics, etc. were appointed full time positions in their program. They maintained a pretty deep "talent pool" for many years to represent them in FAI competition.
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Old 01-26-2015, 01:56 AM
  #35  
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Combatpigg: Sure, that was the case! I was racing against the "professional FAI pilots" quite frequently as I live in Finland Some 50 kilometres away to the south is Estonia , over the Gulf of Finland , the hot place especially for Soviet Combat pilots as Baltic states were all part of the empire ( now NATO countries).. The quality was high, and they were very serious about it, for the greatest part because it allowed them to travel to west to competitions and see with their own eyes, what was the reality here. Somebody might not like, if I tell the "other side of the coin": That was, they had to attend, after being chosen to CCCP team, spend week in "political training" that included the fact that their families were actually hostages, in a situation they would not return home. It also had one , for us funny feature: They actually didn`t perform to the max. They said : Just enough to make the team, with room for improvement,. in case some "outsider" tried to sqeeze them out of the free trip to those horrible capitalist countries... So they were UTTERLY PROFESSIONAL, in every sense of the word. Now when there is no state support, or free trips, Those best machinists have turned to enterpreteneuers that squeeze the most (money) of their very well made products. The quantities are very low, but still much more than in Soviet time, when a couple engines and models was a OK production run per year to reach their goals. In my mind, they could use some inspiration from Western model engine trade, where Italian Picco-Novarossi etc grind out some 1000 to-10.000 engines per month with similar quality and precision, not to talk about COX engines with over million engine production runs and price tag of removing one zero from the retail price of present day Russian/ukrainan competition F2A engines ( $ 1000,- >>> ..$ 100,- ).
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Old 01-26-2015, 08:33 AM
  #36  
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Raddaddy....When the USSR failed, how did that effect the prices of model plane equipment and other every day supplies in Finland. ?
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Old 01-26-2015, 10:41 AM
  #37  
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Answer: We had a flood of USSR stuff coming over, some of it..just pure junk, something quite ok. The specialty guys like those"Professionals" could sell their stuff legally, but the resources like Titanium, other exotic stuff very soon dwindled as the strategic missile plants, where the FAI guys were actually working as "scientists" just closed down ( and the Ogliarcs stole everything there was). I have a funny story about one of such scenes.... One of the "businessmen of new Russia" wanted to buy some exotic cars from Europe- via Finland of course. He ordered his ferrari and was given notice that the car was ready, only the money to buy it was missing. The guy said: NO PROBLEM, you will have your money in a short while, I will arrange it... The seller Ferrari guy was given instructions to be at the border of Russia and eastern Finland in a given day. It was railway terminal for freight. The guy went there and what he got was a three railroad cars FULL OF PRESSED METAL CONTAINERS, hundreds of them stacked up on each other. WHATTA HELL??? The guy said, wait.. take one metal container a lab to analyze the metal... LO and Behold the railroad cars were full of those unsuspicious cans made of PURE 100% TITANIUM. He had them made in MURMANSK, at the secret Atomic submarine plants where they just tore down those subs as there was nobody either watching or paying for the upkeep of the subs !! The only thing you had to do was to take the titanium to be melted and you had several TONS of purest 100% TITANIUM INGOTS.
This was happening all the time, everywhere. When I visited Former leningrad, now St petersburg, they even stole the rail tracks of the trams, nails to fix them into ground, whatever... It was like "Wild west" just with the difference that the "gold " was lying on the ground, You had just to arrange the shipping and you were "businessman"

About the everyday supplies in Finland ( a capitalist /democratic country, since 1917 the revolution, when we threw Russians out from Finland) The time after collapse of USSR turned to be the all time best time in Finnish business and daily life.
It was the time when internet-mobile phone business turned really big for us. NOKIA Mobile phone brand became #1 in the world,counting some 20% of the total industrial production of Finland. It also made many of my friends extremely rich as the share of Nokia rose some 40% in value EACH PASSING YEAR. Now all this is gone, We share the same austerity as other EC countries, well... EURO currency is still OK, as when we started with Euro, it was one euro against two US Dollars. Now it is one and half ( about) euro against US dollars, so we were doing OK, or--you are doing much worse, depending from how you look at it. Anyway the balance of economics is relatively good, we have all the goodies ( scandinavian welfare) what Obama tries to get thru, free schooling, also in the universities,we have the #1 highest schooled kids in the world, without parents having to spend a single dime to have it, free lunch for kids and students. Free healthcare. You pay € 25,-per day in a hospital and you can get for that money a neuro surgery or heart transplant..! Because of EU and euro, food has become much cheaper.also cars and such. If you don`t like the pricing, you can always order your stuff from,for example germany. I buy my cars, cameras, modeling items and such directly from germany-Italy and France. The parcel arrives to me in three days MAXIMUM, so I can also order Food via postal system. Not bad.. The only thing that remains is the WINTER COLD This is not so bad either, as we are prepared.. WE DRIVE THE SAME 55 TO 85 MILES PER HOUR on our snowy but cleared roads with our four wheeldrive Audi Quattros or 4-matic Mercedes. ( we build Mercedes in Finland, for the Germans ) There will be a severe winter storm in few days attacking NEW YORK, with over ten to fifteen feet of snow. I guess THEY are not prepared....

Last edited by Raddaddy123; 01-26-2015 at 10:53 AM.
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Old 01-26-2015, 12:01 PM
  #38  
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Raddaddy, that was a great recount of your recent history and a great report about life in Finland. What great timing you had [thanks to your parents] to be living during that strong wave of opportunity and prosperity.
The news reports [I saw] about Russia didn't focus on the reckless "redistribution of wealth" that you witnessed first hand.
Life in Finland sounds very good. In order to keep it that way, you people should be very careful about who you allow to enter your country.
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Old 01-26-2015, 12:34 PM
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Thanks, we are.. In the aftermath of WW II we were on the losing side ( with germans) but Finland and our capital Helsinki was never occupied, the only contry Russia didn`t capture. Now when russians are coming here, we say_ You are welcome, but if you come with KALASHNIKOVS, you will have a hard time...
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Old 01-26-2015, 03:25 PM
  #40  
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What sort of model flying is popular in Finland today..?
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Old 01-26-2015, 03:30 PM
  #41  
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How much big end journal clearance is too much / too little? The Conquest rod is oversize, bit these don't have to be super close fit, do they..? I thought .002-003" was ok but maybe that's for much bigger engines, forget.
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Old 01-26-2015, 03:49 PM
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There isn't any sort of "inch measurement" that us hobbyist would take for the final fit. You have to go by the feel. The rod should swing freely on the pin, but with zero slop. You would take a snug fit, then lap the final fit with a fine grit, oily paste. Sink cleanser and oil.
An assembler in an engine factory might have bins full of microscopically different rods and cranks sorted by size ...[at least in olden times]. The skill was to quickly combine the right combination of parts to ensure that no engines issued were either too tight or too loose.
Imagine how difficult that chore became once ABC engines were introduced. I suppose you would take a calibrated amount of effort to push the piston up inside the cylinder until it halted and a predetermined height.
A well fit rod assembled inside the engine should only allow 10 degrees of crank rotation either side of BDC [without the piston moving]. I've referred to this before as "dwell" for lack of a better term.
Even this sounds kind of loose, but I've found 10 degrees to be fairly universal.

Last edited by combatpigg; 01-26-2015 at 03:54 PM.
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Old 01-26-2015, 04:27 PM
  #43  
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Well, that's good info, thanks. It turned freely and seemed "good", but it either went dry, or... what I think may have happened is the big end picked up some fine aluminum swarf as it kissed the backplate.

I'll have a look at them Traxxas parts, I think the LHS stocks that stuff.
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Old 01-26-2015, 04:31 PM
  #44  
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Originally Posted by Raddaddy123 View Post
A hot tip is that both this engine and the TRAXXAS 15 car engine are almost carbon copies internally to Rossi mark II. You can get very good P/C , rod and various other parts just to ordering them from your hobby shop. Just take the parts of MDS with you and measure you have the right version of Traxxas 15. But still, I just bid 2ea NOVAROSSI 15 Aero Speed engines in Ebay for F2A treiner use for about 150 dollar total (less hipping) I would use the MDS spinner assy, the pipe and the pipe silicon joint ring and simply toss everything else.
This looks hopeful:

http://www.greathobbies.com/producti...rod_id=TRX4030
http://www.greathobbies.com/producti...rod_id=TRX3224


http://www.greathobbies.com/producti...od_id=TRX5230X
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Old 01-26-2015, 05:32 PM
  #45  
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Answer to both CombatPigg and MJD: We in Finland do most of the different model flying varieties as in the USA. Maybe the main difference is that we have very few contest classses and FreeFlight/oldtimers are almost non existing ( I am building soon a FF Ramrod 250 with an authentic Thermal Hopper 049 with the proper birdcage mount. That model flew away on it`s first flight in my first competition test flight as I could not expect it to fly so well and didn`t light the DT fuse.
The contest classes entered in Finland are FAI F2A, F2B (stunt) F2C presently there are no teams participating, but Finland team has been a Euro Champion in this class. F2D (combat is very strong here with good material coming from russia
You can buy World Class equipmentReady to go to most of the FAI Classes, including F1 free flight classes, but the price is whooping, a F1 class freeflight with a glo 15 engine, gearbox, folding prop and brake, with all that complex timer stuff, variable incidence, pop out wingtips, can cost you well above three grand US Dollars people buy lots of Russian Gliders,F3A big stunt plane, Ducded fan or kerosene burning miniature jet planes with airframe made in Russia.
Then we have the Chinese origin ready to fly models.I personally like the indoor precision stunt planes (slow flyers) and now the multirotor dones
My main activity, though is to be a "Team boss" For a 1/8 RC on road Nitro car team. I used to do it myself driving, being Finnish Champion many years ago, but now I concentrate on team leadership. I do lotys of Nitro 21 engine work for both the on road and also for 21 marine nitro engines both Hydro and so called OTA cat class, where we run 21 outboars, fitted with converted car engines, with a tuned pipe, styeel prop and a lot of NITRO.
I have flown in the past F2A and being a mechanic in F2c dieselized team tace team. For a while I did Tether cars as I could not anymore cope with the athletic part of F2A, my best was with a Cyclon 15 some 285km/h not a top world class result, but halfway in the score of today`s WC results. My Finnish records in tether cars are 312km/h in 10cc class with a modern tether car/Picco EXR powered and 265 in 5cc with an estonian built Novarossi tether car. If somebody breaks my record in Finlanf.I will go back and do some more racing... hehe So I am the distributor for german SHEPHERD VELOX V 8 on road nitro car, have 2 top rc pilots in the team and also 2 mechanics, I finance the team with the technical support coming from the Shepherd factory. We are the 2014 Finnish On Road 1/8 Nitro series winners, with new program to go to the European continent in 2015 to compete in the EURO NITRO ON ROAD SERIES, with races in Germany,Italy ,Swizerlandto face the other big teams When you go to a hobby shop in Helsinki, all the major brands are there, Sullivan-Great Planes- Futaba/sanwa (airtronics) Traxxas-Aquacraft-Thunder tiger. If we don`t find there what we want, we shop by internet. Credit card and paypal deliver you what you ever want

To MJD: Check out a tool with correct size- a kind of reamer with very slight increase in hole diam. With that you can open up a rod end to just the right size. it also gives you bearing surface that is ok, not filled with any burrs or grind paste that just messes your fit when you start to run the engine. If you have a hydraulic drill press ( several tons) you can squeeze the rod end bearing slightly to bring it to a good tolerance. I do it in 21 team engines, if there is no replacement rod available and the engine (P/S fit ) is otherwise good.
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Old 01-26-2015, 06:01 PM
  #46  
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WOW..! To say the very least you are a very busy guy in this hobby..!
Congratulations on your national records, too.
I've read about Finnish F2d flyers through the years in the World finals.
I've never heard of "squeezing" a rod, but I've heard that some RC car users have "pinched" the worn out liners [in a split bushing that is squeezed by a large lathe head].
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Old 01-26-2015, 08:28 PM
  #47  
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Let me put my $.02 in. I used to have a hobby shop. Billy Hughes will know me from the time I showed up at Toledo with an absolute treasure trove of speed engines. There were 176 in all and the were all very high level competition speed engines I had bought in an estate. I used to supply most of the Super tigre x-40's to the Formula I guys. I bought about 150 of these MDS engines and I think I sold them for $70 retail and I sold almost all of them. I probably have about 10 left somewhere. There was a well known speed flyer in California that was a professor at a University and he had several students buy these to get started in A speed. They were doing about 165 on monoline..
That estate had about 15 Rossi's, 20 Irvine .15 and .21 speed, 3 Hallman specials, 2 Hofflet combat. 10 OS 65VFDF,6 ST X .29's, about 8 Wisnewski factory specials, a dozen Cossi's and on and on. Like I said a real treasure trove of engines.
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Old 01-27-2015, 12:17 AM
  #48  
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Both "tools/ First air remedies" are used frequently, the rod lower bearing squeeze being the easiest. I have a russian tool for pinching but I must say, it takes lots of experience and patience to shift the pinch position around several times to make the sleeve truly round. Otherwise you have a tight sleeve that is oval and in the first run turns to be EVEN looser !The best way to check this is to put the piston with rod BACKWARDS in the sleeve so the taper shows somewhere in the piston wall,. halfway to the top (now bottom) if the shiny mark in the sleeve wall and piston is a continuous shiny band. If it is and the piston is snug fit (in cold state) some 1-2 mm from the top dead center, you can be sure you have a killer fit that will last for several rounds of hard usage. PLS note: it is very good if you will accumulate a slight coloring of castor in the band where the compression builds up. It is the "sliding surface" that don`t wear away. One lean run, however, piston expands and it is gone.. back to "Shrinking the sleeve" Take it as a habit to examine the state of that band in the piston from exhaust port to know how the all important surface is. Brown ok, slightly grey... on the limit, but shiny: You are on your way to destroy your Piston/Sleeve fit. You can ask me whatever you like about Nitro/methanol engines, I have done it for sometime, all the way from Dooling 29 and Fox 29R bath thub engines in late 1950`s. had the first Super Tigre ABC engines. The ABC set up was invented by George Aldrich back in the early 70`s when he was doing development work for WORLD ENGINES, the U.S.importer of Super Tigre.. I had Veco McCoy by GMA in my championship winning Associated RC 300 car that had all the mods George could come up with ! Great times, with new ideas appearing in almost every new contest. Now the development has stagnated to improving the publicity power ratings in the engine leaflets. I have some reference engines: K&B 3,5cc by Bill Wisniewski and the first Novarossi 21 car engine. In bench running with a calibrated prop the improvement or lack of it will show mercilessly. For you to know: The max power of the nitro engine is mainly dependent of these factors:
Compression ratio, balanced to have the "ignition on the most effective timing spot" that take into count the fuel, glow plug heat range, needle setting and exhaust system dimensions. That is hard puzzle to be mastered as it changes the variables most of the time. F2A speed is class where the mastery of all these (except nitro content- the class uses 80/20 mix of pure methanol and first pressing castor ...NO ADDITIVES.. Klotz Benol is not an official oil for F2A) decide the winner in WC and other contests. Current F2A props are one blade, so quick change in pitch is possible with a angled spacer. prop away, little less pitch, prop back and you have changed the set-up fro "Fifth gear to fourth gear" and you are able to peak the enigne, when all other variables stay the same...
The most potent Russian speed engines are internally actually very simple, regarding the shape and number of ports. All this 5-7 port CAR engines focus on FUEL MILEAGE, you have 125cc of fuel and you have to use it wisely, to end the 5 minute heat t with the available power..
For Speed /aero work, those intricate ports are waste of money. You end up with similar or better results with 3 port basic Schnuerle porting, when all the other variable are right.
Think friction as a limiting factor in Nitro glow plug engine. Of course the fit, bearing conditions, BUT ALSO FRICTION OF AIR STREAM inside the engine. Polishing the passages inside may seem to be a good idea, but it is not. Shiny surface will make a laminar flow inside, but slightly irregular surface makes the flow break away from the surface and actually causes LESS friction in the air stream inside the engine passages and ports....funny, isn`t it ??
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Old 01-27-2015, 12:59 AM
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combatpigg
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I am glad to hear that the basic 3 port configuration is still hard to beat.
Your advice makes good sense about pinching the liner "progressively".
I've got a few engines to try that trick on.
I know a guy who swears he was able to increase the diameter of a Cox leaded steel piston with heat. I tried it and only managed to turn it into a puddle of molten slag.
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Old 01-27-2015, 05:06 AM
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You CAN increase the diam of aluminum/silicon piston by heating it to high temp. Then you have to drop it in very high heat state to cold water, prefarably salt water. It will "freeze" in expanded state. I give you here another hint on cold/hot massge: it is about tuned pipes or spun exhaust mufflers. If you have bad dent, don`t put any hard object in it to bend the dent out. Just fill with water almost full. close then the ends with paper towel plug and put in a freezer. When water becomes ice.it expands and the dent pops out, nicely and smoothly, without any bad marks. Then just polish it with aluminum polish and yo can sell the pipe as almost as new...
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