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Old Sep 21, 2012, 09:35 PM
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Reedy vs Tee Dee

If you polish the crank and lap in a Killer Bee or a Venom reedy as Geibault the mouse racer suggests, with a pinch of luck you can get one that'll run with Tee Dees. OK, maybe with an extra 10% nitro. Anyway, if they'll turn the same RPM, would the power/torque curve be about the same? I'll bet you they aren't identical.
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Old Sep 21, 2012, 10:22 PM
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Polish the crank too much and it leaks air out the front end and won't keep a setting. Reedies are never as good as a TD. You can modify a TD too, and less maintenance and no orings and reeds to replace.
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Old Sep 22, 2012, 03:04 AM
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Polish the crank too much and it leaks air out the front end and won't keep a setting. Reedies are never as good as a TD. You can modify a TD too, and less maintenance and no orings and reeds to replace.
Yes, the reedys are limited, a little like racing VWs. But, having learned on a Cox TD4 then PT19s and then gone on to sophisticated stunters and my modified Nemesis fast combat planes, I now, in my later years, want to build a reedy to the max and then mount that on a very light Baby Flight Streak. Sort of a tribute those reedies I flew, learned 90% of all I know about CL flying, cursed at and was finally glad to leave for better engines 50 years ago. Do you think the power/torque curves are the same on engines turning the same RPM?
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Old Sep 22, 2012, 10:12 AM
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Polish the crank too much and it leaks air out the front end and won't keep a setting. Reedies are never as good as a TD. You can modify a TD too, and less maintenance and no orings and reeds to replace.
Yes, BUT:

1. Both are out of production, MANY times more reedies made, so easier/cheaper to find and buy.

2. Glow engines are being pushed out by electrics, so enjoy them while you can.

3. The comment is about 20 plus years out of date; see one and two above.
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Old Sep 22, 2012, 11:06 AM
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I think a reedie will run a bigger prop because the reed allows the amount of fuel mixture it wants instead of it being regulated by a port. It also is better at low rpm's because the reed maxes out at higher revs. At higher revs, a front intake would win for power, a reedie might win for torque at a very low rpm. Then there are diesels. As for comment 1 and 2 above, I found lots of TD's at swap meets and still enjoy them while I can. Every time I run a reedie I always think how much better it would go with a TD except for one oldtimer I have that would be overpowered. I probably have close to a dozen of them just in case. My club requires a muffler so it is hard to use them up. I found the mufflers take away too much power on the .049's.
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Old Sep 22, 2012, 01:21 PM
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I think a reedie will run a bigger prop because the reed allows the amount of fuel mixture it wants instead of it being regulated by a port. It also is better at low rpm's because the reed maxes out at higher revs. At higher revs, a front intake would win for power, a reedie might win for torque at a very low rpm. Then there are diesels. As for comment 1 and 2 above, I found lots of TD's at swap meets and still enjoy them while I can. Every time I run a reedie I always think how much better it would go with a TD except for one oldtimer I have that would be overpowered. I probably have close to a dozen of them just in case. My club requires a muffler so it is hard to use them up. I found the mufflers take away too much power on the .049's.
I have drawers full of them myself. Diesels are a different breed. The ball and socket at the piston and the puny rod on the Cox stuff don't adapt well too it.
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Old Sep 22, 2012, 02:19 PM
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Polish the crank too much and it leaks air out the front end and won't keep a setting. Reedies are never as good as a TD. You can modify a TD too, and less maintenance and no orings and reeds to replace.
I hate to point this out, but if you have a good tweeked RR-1, it will blow a TD into the weeds.
Yes, it isn't a reed valve, but the rear rotors always ruled speed.
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Old Sep 22, 2012, 02:23 PM
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The reed valves are fortunately still available from Bernie at Cox International, Canada and a few others. These are mostly the Sure Start format, although he has others with better performance. They have their place, where the power of a TD or Norvel aren't required, although I must admit I have heard what tigreflyer alludes to mods where power approaches that of the TD. Somewhere back around 40 years ago, there was a CL class where the reed valves were raced.

On the Sure Starts, I gather the one mod for power is boring out the backplate throat after removing the screen and needle assembly. Then one tinkers with heads, cylinders, intake flutes, etc.

A true Venom was supposedly one of the hottest .049 reed valve engines. I heard that when Estes took over the Cox inventory, that quality control started to suffer. I think Bernie and others who have purchased that inventory are doing a better job of quality control with better consistency in what they sell.

Yes, it is a slowly fading history, still to be enjoyed until totally dominated by electrics. I've got a Sterling Beginners Hellcat and 2 Estes Star Wars X-Wing and Y-Wing 1/2-A CL kits to complete. The Y-Wing enlarged would make an interesting R/C model, but I would probably modify it slightly so to avoid copyright infringements with the movie industry with the potential lawsuits.
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Old Sep 22, 2012, 02:30 PM
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The reed valves are fortunately still available from Bernie at Cox International, Canada and a few others. These are mostly the Sure Start format, although he has others with better performance. They have their place, where the power of a TD or Norvel aren't required, although I must admit I have heard what tigreflyer alludes to mods where power approaches that of the TD. Somewhere back around 40 years ago, there was a CL class where the reed valves were raced.

On the Sure Starts, I gather the one mod for power is boring out the backplate throat after removing the screen and needle assembly. Then one tinkers with heads, cylinders, intake flutes, etc.

A true Venom was supposedly one of the hottest .049 reed valve engines. I heard that when Estes took over the Cox inventory, that quality control started to suffer. I think Bernie and others who have purchased that inventory are doing a better job of quality control with better consistency in what they sell.

Yes, it is a slowly fading history, still to be enjoyed until totally dominated by electrics. I've got a Sterling Beginners Hellcat and 2 Estes Star Wars X-Wing and Y-Wing 1/2-A CL kits to complete. The Y-Wing enlarged would make an interesting R/C model, but I would probably modify it slightly so to avoid copyright infringements with the movie industry with the potential lawsuits.
I have a real sweet Space Hopper- flips back and forth like it has ball bearings- an example of a time when Cox quality control was at it's zenith. At one time, the Space Hopper held the AMA 1/2A Speed record. Don't underestimate the reedies!
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Old Sep 22, 2012, 04:51 PM
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Whenever it was that they were fairly new, I had Thermal Hoppers, but the various "Bee" critters wouldn't hold a candle to the Thermal Hoppers. I flew some Half-A Free Flight in the early 1950s . . but combat soon ate every spare bit of my hobby budget, when I needed to move past my GH Torps to faster, longer-lived engines, and more than a couple of them, to be prepared for an inevitable "broken -- out of service" situation when a hidden rock in the dirt / grass managed to be right where the crankshaft wanted to go!


Kiwi .
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Old Sep 22, 2012, 06:21 PM
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Polish the crank too much and it leaks air out the front end and won't keep a setting. Reedies are never as good as a TD. You can modify a TD too, and less maintenance and no orings and reeds to replace.
You can ruin a TD too, same way- can a good reedie beat an average TD? Yep...
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Old Sep 22, 2012, 06:59 PM
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I never had a Space Hopper, so I couldn't say about them, but will go out on a limb and say a good stock reedie will not beat an average TD. Most never had twin ports except maybe a Black Widow. The intake hole is about 1/16" dia. Oh ya I raced them about 40 years ago. I was a little kid though, but I'm a big kid now. I think I still have a mouse racer with a stuck reed that is otherwise ready to go. A Surestart with a huge intake and TD parts could go very fast with a bladder and a lot of nitro. I would have to make a phone call to get the speed but remember my flying buddy had a reed speed going quite fast that way. It had a B Bee tank with a 1/8" hole and a TD spraybar and cyl. used a dolly etc. We still went faster with TD's but not much better than that one. I think we were around 100 mph with the TD. I know the Reed Speed was much faster than a mouse racer but can't remember the mph. 70 or 90 mph? Likely 70
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Old Sep 22, 2012, 07:15 PM
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I never had a Space Hopper, so I couldn't say about them, but will go out on a limb and say a good stock reedie will not beat an average TD. Most never had twin ports except maybe a Black Widow. The intake hole is about 1/16" dia. Oh ya I raced them about 40 years ago. I was a little kid though, but I'm a big kid now. I think I still have a mouse racer with a stuck reed that is otherwise ready to go. A Surestart with a huge intake and TD parts could go very fast with a bladder and a lot of nitro. I would have to make a phone call to get the speed but remember my flying buddy had a reed speed going quite fast that way. It had a B Bee tank with a 1/8" hole and a TD spraybar and cyl. used a dolly etc. We still went faster with TD's but not much better than that one. I think we were around 100 mph with the TD. I know the Reed Speed was much faster than a mouse racer but can't remember the mph. 70 or 90 mph? Likely 70
I have a nice wood saw for your limb...
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Old Sep 22, 2012, 07:24 PM
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What was the reason for the TD series?

1. Simpler to make.

2. Cheaper than further developing the RR-1.

3. Read one and two above.
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Old Sep 22, 2012, 07:27 PM
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Got a chuckle out of that one. Sounds like a tachometer challenge to someone. Stock to stock reedie and TD. Anyway I got a pic of my old 1/2A proto with a TD from the 1970's and a profile proto with a CS from a bit later if I can load it. Have to kick myself for not getting the RR 1 at the swap meet last year.
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