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RCGF Engines

Old 11-13-2011, 11:55 AM
  #5701
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O M G
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Old 11-13-2011, 02:25 PM
  #5702
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Quote:
ORIGINAL: airtime82

How can you tell if the engine you have is in timing when you get it?
If you got it through a decent dealer, it will have been checked. If you didn't get it through those means.
Check that it is firing somehwere between 25 - 30 degrees BTDC. (28 is ideal but a couple of degrees either way is not going to make one iota of difference to the final outcome).

For a quick and dirty test

Find TDC by looking at the piston through the exhaust port. - mark a pencil line across the prop hub and the crankcase at this point.

Method one for finding the right firing point
Get a strip of paper and wrap it around the prop hub. Cut it so it is exactly the length of the hub circumference.
Get that piece of paper and cut it in half - discard one half.
Get the piece you kept and cut it in half again - discard one half.
Get the reamianing piece and cut it into a 1/3 length - discard the 2/3rds length.
That last peice you kept is now "30 degrees" long. Make a mark from the exisiting mark on the hub to the length of that paper before TDC (to the left of the mark looking from the front of the engine.

Method 2 for finding the firing point.
Measure the diameter of the prop hub and muliply it by 0.244 - that is the 28 degree length. use that measurement to amke the BTDC mark.

Now power up the ignition, and listen to the spark plug cap - it will make a "crack" noise when it fires. Do it slowly and don't overdo it. There is no need to have a spark plug in there for this test as the occassional use of it this way woun't hurt a thing.

Now you will most likely have discovered that the timing is way out - go dril some new mounting holes for the sensor screws or start filing the senso slots to get the sensor to the right place as my experience has been they are either close enough or a long way out.
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Old 11-13-2011, 03:41 PM
  #5703
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Default RE: RCGF Engines

hmmm helpful
Quote:
ORIGINAL: acerc

O M G
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Old 11-18-2011, 08:16 AM
  #5704
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Default RE: RCGF Engines



I just finished the last of my fifth gallon of gas thru this engine. Somewhere in the last two tank's the engine started to open up. I'm currently running an 18-8 @ 7000rpm with full synthetic @45-1. Thinking of going to an 18-10 prop just to maintain some load on the engine in the air. The plane weigh's 17lbs and will almost hover. And for a Waco that look's odd. Also I am getting about 40 min's flight time on a 16oz tank. And this is not running lean, Itach tomaxrpm and back down 2-300rpm's.
I don't know if that's good or bad but compared to nitro, well,there's no comparison. Any of you guru's see something in this I may need to take a better look at by all means let me know.
airtime82, my appoligies on the O M G. Just one of those days, and one of those questions thats been asked 300 times. But that is why we come here.

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Old 11-22-2011, 09:15 AM
  #5705
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Default RE: RCGF Engines

Been working onanother RCGF 26 in a cub. Runs great same as the others. Only the prop bolt is boogered up a little. The locknut goes on good but upon removal the plastic (the lock part) is ate up. So I have to replace the nut everytime I remove it. Talked with BP about the replacement and will order a new one. Would have been nice if they had offered to replace it. But hey it's only ten buck's.
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Old 11-22-2011, 10:05 AM
  #5706
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Old 11-22-2011, 11:35 AM
  #5707
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Default RE: RCGF Engines

Hey Acerc,

What part of are you replacing, the nut or the prop shaft? If it is the prop shaft the problem may not go away. The factory cuts them to the right size and then someone feels for some reason that the part needs to be chrome platted. I can’t tell you how many of those that I have re-cut the threads on. Anyway just go get an 8mm dye at ACE hardware and re-cut the threads on your prop shaft. Problem solved. The dye and T-handle will cost you a bit more I think 12 to 14 dollars but you will have the tool the next time you need it.

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Old 11-22-2011, 11:51 AM
  #5708
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Default RE: RCGF Engines

Hi Does someone have a complete manual for the 15cc engine? I'm glad i read this forum, would have never thought to check the timing of the engine.

I was looking for the performance curves of these engines but could not find them. Sent a mail to the manufacturers but they replied with a statement saying they don't have any... How is that possible? They state the kw rating of the engine but they don't know at what rpm they achieved it or anything... Stated bore and stroke is also wrong. It's 31mm and 24mm stroke. If you take into consideration the exhaust port ect it does come out at 15cc, so atleast they wern't lying about that.. Anyway, if anybody could help I would appreciate it.

Fuel consumption vs load and power vs rpm and fuel vs rpm


The Old Grey Grandpa AKA Oupagryse in Afrikaans


@ ACERC P.s a Nylock nut is only suppose to be used once... The plastic bit should be threaded, you can use them about 3 time before they stop the nut from vibrating loose..
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Old 11-22-2011, 12:52 PM
  #5709
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Default RE: RCGF Engines

W O W ! Captmicom, you are the man. After reading your post took a look at it under a magnifying glass and wah-lah. There are all kinds of little spec's sticking out on it. Look's like a bunch of sand got tossed on it while plateing. OH yea, It's the shaft.
Thank You Sir!


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Old 11-22-2011, 02:24 PM
  #5710
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Default RE: RCGF Engines


Quote:
ORIGINAL: Oupagryse

Hi Does someone have a complete manual for the 15cc engine? I'm glad i read this forum, would have never thought to check the timing of the engine.

I was looking for the performance curves of these engines but could not find them. Sent a mail to the manufacturers but they replied with a statement saying they don't have any... How is that possible? They state the kw rating of the engine but they don't know at what rpm they achieved it or anything... Stated bore and stroke is also wrong. It's 31mm and 24mm stroke. If you take into consideration the exhaust port ect it does come out at 15cc, so atleast they wern't lying about that.. Anyway, if anybody could help I would appreciate it.

Fuel consumption vs load and power vs rpm and fuel vs rpm


The Old Grey Grandpa AKA Oupagryse in Afrikaans


@ ACERC P.s a Nylock nut is only suppose to be used once... The plastic bit should be threaded, you can use them about 3 time before they stop the nut from vibrating loose..
31mm bore and 24mm stroke comes out at 18cc.

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Old 11-22-2011, 11:22 PM
  #5711
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Default RE: RCGF Engines

Acerc a 10 pack of m8 nyloc nuts should be about $1 dollar at the local hardware store!.
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Old 11-23-2011, 12:58 AM
  #5712
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Default RE: RCGF Engines

Nope... If you just take the stoke as is... Many people make this mistake.(can't tell you how many people i've come across, saying engine specs are wrongect becuase they can't domath).Power is only generated under compression... If you look at a two stroke the exhuast port is part of the stroke, so the actual power stroke is the stroke length minus the height of the exhuast port... Then there is alsothe gap at the top of the engine for the sparkplug.. Engine size is something like 15.8cc.. Remenber... Engine capacity isn't just bore*stroke!

Regards

@raydar I totally agree, It is 40c in rand terms, so that is about $ 0.05 per nut... Not all that expensive...
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Old 11-23-2011, 07:26 AM
  #5713
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Default RE: RCGF Engines


Quote:
ORIGINAL: aussiesteve


Quote:
ORIGINAL: Oupagryse

Hi Does someone have a complete manual for the 15cc engine? I'm glad i read this forum, would have never thought to check the timing of the engine.

I was looking for the performance curves of these engines but could not find them. Sent a mail to the manufacturers but they replied with a statement saying they don't have any... How is that possible? They state the kw rating of the engine but they don't know at what rpm they achieved it or anything... Stated bore and stroke is also wrong. It's 31mm and 24mm stroke. If you take into consideration the exhaust port ect it does come out at 15cc, so atleast they wern't lying about that.. Anyway, if anybody could help I would appreciate it.

Fuel consumption vs load and power vs rpm and fuel vs rpm


The Old Grey Grandpa AKA Oupagryse in Afrikaans


@ ACERC P.s a Nylock nut is only suppose to be used once... The plastic bit should be threaded, you can use them about 3 time before they stop the nut from vibrating loose..
31mm bore and 24mm stroke comes out at 18cc.

Oupagryse is correct, on a two stroke engine, you measure the compression chamber from the top of the exhaust port. I work with two stroke engines in my line of business and thats the way to do it correctly.

You can also ..tinker...with the exhaust port timing some to get more rpms if you are racing Just shave some off the TOP of the exhaust port to increase rpm. BUT, as with all engines, to gain one is to loose one. By doing the port timing change, you gain rpm but you loose idle stability and torque. So if you have a light plane that you want to make go fast, change away . I used to do about .oo2 inches at a time till I got what I wanted. If you go to far, you kill the engine by going over the power curve and then your on the back side of the curve. No way to fix that but replace the cyl assy. LOL

Just experience over the years.


An easy way to find the point to meassure from on the exhaust port, that Ive used, is in a darkened room, shine a light into the exhaust port from muffler side , with piston at tdc, looking down into the cyl, rotate (either way) till you just see light enter the cyl through the port. Stop and mark location somewhere on the crank and block. This is your start point to measure the actual stroke of the motor.

Hope this helps

What I like about these forums. Ive learned some things and Ive shared what I know. Gotta love it We all have one goal. This forum helps us all to reach it.

WBG
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Old 11-23-2011, 01:55 PM
  #5714
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Default RE: RCGF Engines

Would like to send a Thank's to BP Hobbies. What a great group of people. Especially Gregg. They are sending me a new shaft,  free of charge.
Outstanding!!!


Thank's
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Old 11-23-2011, 02:03 PM
  #5715
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Default RE: RCGF Engines

Yes I am aware of the "effective sweep volume " of the piston however the standard takes the entire stroke into account for displacement calculation. In a running Engine, even while the exhaust port is open there is still transfer taking place and cylinder charging taking place whilst the port is uncovered.

Comparing on the same measurement basis - sure makes the DLE 20 appear to be a significantly better desing than the others doesn't it - it uses 20cc of total displacement - including the port open volume.

Sorry guys - ya walked right into that one.

Back to the original programming.

And Kudos to BP for taking care of Roberts shaft.
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Old 11-23-2011, 07:09 PM
  #5716
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Default RE: RCGF Engines


Quote:
ORIGINAL: aussiesteve

Yes I am aware of the ''effective sweep volume '' of the piston however the standard takes the entire stroke into account for displacement calculation. In a running Engine, even while the exhaust port is open there is still transfer taking place and cylinder charging taking place whilst the port is uncovered.

Comparing on the same measurement basis - sure makes the DLE 20 appear to be a significantly better desing than the others doesn't it - it uses 20cc of total displacement - including the port open volume.

Sorry guys - ya walked right into that one.

Back to the original programming.

And Kudos to BP for taking care of Roberts shaft.

Walked into what? Your wrong idea about? If your talking 4 cycle, then yes. You measure the entire stroke from bottom to top because you have a seperate valve that shuts when the piston reaches its bottom of the stroke. You have the entire stroke to build compression. Not so with 2 cycle, as already explained. Maybe yall do things different in the land down under. But in the real world, not done that way

buyah! you ran right into that one.

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Old 11-23-2011, 07:44 PM
  #5717
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Default RE: RCGF Engines

Ya reckon so?

It is about Engineering and marketing STANDARDS.

The STANDARDS for stating displacement is Bore and stroke - not minus anything else.

Funny thing is - if the company involved atated the actual displacement based on those same standards, they would probably sell more enignes becaus "everybody" knows people will buy an 18cc over another brand of 15cc because it is bigger for the same sized package.

But then maybe ALL the other 2 stroke manufacturers in the world don't know what they are talking about. Honda, Kawasaki, Yamaha, DA, 3W, MVVS, Detroit Diesel, and the list goes on and on.

Those companies use the full stroke and bore to state cubic capacity. By using the same basis for stating it on an RCGF / GRPro / SV product it really shows up a low power to displacement. Eg - the 15cc is really 18cc using the STANDARD method of statement, the 20cc is really 23cc using the same method of statement - now use those and compare power outputs against the opposition products.

That is all I am saying on the subject - back to the normal channel now - buy and fly what you like.

Oh, I almost forgot - "Nice plane"

(seems to be a pretty common answer for "Darned if I know the answer to the question posted" around some parts of the forums these days)
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Old 11-23-2011, 08:14 PM
  #5718
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Default RE: RCGF Engines


Quote:
ORIGINAL: aussiesteve

Ya reckon so?

It is about Engineering and marketing STANDARDS.

The STANDARDS for stating displacement is Bore and stroke - not minus anything else.

Funny thing is - if the company involved atated the actual displacement based on those same standards, they would probably sell more enignes becaus ''everybody'' knows people will buy an 18cc over another brand of 15cc because it is bigger for the same sized package.

But then maybe ALL the other 2 stroke manufacturers in the world don't know what they are talking about. Honda, Kawasaki, Yamaha, DA, 3W, MVVS, Detroit Diesel, and the list goes on and on.

Those companies use the full stroke and bore to state cubic capacity. By using the same basis for stating it on an RCGF / GRPro / SV product it really shows up a low power to displacement. Eg - the 15cc is really 18cc using the STANDARD method of statement, the 20cc is really 23cc using the same method of statement - now use those and compare power outputs against the opposition products.

That is all I am saying on the subject - back to the normal channel now - buy and fly what you like.

Oh, I almost forgot - ''Nice plane''

(seems to be a pretty common answer for ''Darned if I know the answer to the question posted'' around some parts of the forums these days)
Steve,

I have not followed this thread at all but have heard that their 32cc is very strong. Do you know what their 32 is like?
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Old 11-23-2011, 10:41 PM
  #5719
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Sure Steve will confirm. IMV RCGF 32cc is a very good engine from what I see at my club. Same class as a DLE30, maybe better. Couple of my mates running them in Pilot RC SBach 342, YAK54 and Extra 260 's and they are superb performers. Instant throttle response and swinging 20x8 props.
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Old 11-23-2011, 11:04 PM
  #5720
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MTK,

I concur with TimBle. I am flying 3 of the RCGF 32cc v2 engines. I have one in a 100” wing span Howard DGA 15, that is a Mr. Mulligan with more wing. I have to fly it at half throttle swinging a Xoar 22x8 to keep its character close to scale. My wife’s 26% YAK 54 hovers at half throttle. The Giant Stik I won’t even comment on the sick things the kids do with it but it really sets off the older flyers. [:@] It is a good all around power plant for the money. Just be sure to buy from a good dealer that will back you up just in case there are any problems.

Captmicom[8D]
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Old 11-24-2011, 07:01 AM
  #5721
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Default RE: RCGF Engines



From personal experience I recommend BP Hobbies. They have taken care of me very well. I have three as well and have a couple guy's at the field that havegone to them. They all start first flip, idle well and seem stronger than expected. For example the 26cc specs call for a 18-8 @7100, I'm running a 18-8 @ 7400. Will almost hover my 17lb waco.

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Old 11-24-2011, 04:57 PM
  #5722
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Quote:
ORIGINAL: acerc
I have three as well and have a couple guy's at the field that have gone to them. They all start first flip, idle well and seem stronger than expected. For example the 26cc specs call for a 18-8 @7100, I'm running a 18-8 @ 7400. Will almost hover my 17lb waco.

Robert, an MVVS 26cc with a JTEC Pitts muffler will do better than that, or 18x8 Xoar at around 8,000RPM on the ground
A proper Pitts muffler like the Silent Beauty muffler is far less restrictive and has better flow so you gain another couple of hundred RPM
They are also actual mufflers, not just cans
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Old 11-24-2011, 07:21 PM
  #5723
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That all sounds good. But for the price difference, MVVS @$499and RCGF @ $226, I'll take the loss of 600rpm. Of course once my new JTec pipe comes in that will probably only be a loss of 400 or less. And then add in that BPHobbies has outstanding customer service (where I buy mine) , and that amounts to one happy me.

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Old 11-28-2011, 07:07 PM
  #5724
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Default RE: RCGF Engines

I've seen them post the 40cc twin now.
http://www.bphobbies.com/view.asp?id...9&pid=F3693948

And video is alread posted online.
http://www.youtube.com/watch?v=HYPascJ62aQ

I'm truly interested in this engine...it's performance and reliability. Now to find an airframe for it....
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Old 11-28-2011, 08:38 PM
  #5725
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I just finished the engine set up on the C47 Im building. Here is an idea I had for the choke. I used some 4-40 rod with a z bend to hook into the choke arm. Then I ran the rod through a ply bracket I made that fits the mounting holes. I ran the rod out to where it just clears the prop when choke is in the OFF position. You push the rod in to choke, then pull out to run. Saves using a seperate servo, and keeps it simple. Was just an idea The ignition module is mounted on a platform I fabricated from ply and held down with two tie straps. There is a layer of white foam pad between the module and wood base. I think this will work? Anyone care to make a comment on how the module is mounted? I dont think there would be an issue, but open to suggestions

WBG

Sorry bout the fuzzy picture lol sometimes I can take one clear as day, then the fuzzies show up.
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