Help with Mantis 20 or Echo 21.2
05-17-2007, 07:30 AM
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Help with Mantis 20 or Echo 21.2
I have recently acquired a Mantis 20 engine I think it is an echo 21.2cc engine. This will be my first engine conversion. Is this a good engine to convert? What's sized planes will it fly? I have an extra 300 with a 68 inch wingspan that need to motor will this engine work for this plane? Here are some pictures of the engine. All your help would be greatly appreciated. And if anyone has pictures of this engine converted maybe you could load them here.
Kevin
Kevin
05-17-2007, 07:41 AM
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RE: Help with Mantis 20 or Echo 21.2
There is a tag on the pull start side under the cylinder, what does it say?
How many square inches is the plane?
1200 is a rough size for a gas engine.
Echo 23.6 would be better because of the larger ports.
Do a search on Echo in the conversion forum. There is lots of stuff.
How many square inches is the plane?
1200 is a rough size for a gas engine.
Echo 23.6 would be better because of the larger ports.
Do a search on Echo in the conversion forum. There is lots of stuff.
05-17-2007, 08:15 AM
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RE: Help with Mantis 20 or Echo 21.2
Ralph thanks for the information. The tag says SV-2AE and all the rest information is rubbed off. I am not quite sure how to figure out square inch of the plane.
Kevin
Kevin
05-17-2007, 08:33 AM
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RE: Help with Mantis 20 or Echo 21.2
Google and 30 seconds is all it took.
http://littlewonder.com/12_engine_se...2_pn_385_3.pdf
It's an echo.
I picked up 6 proclaimed dead Echo's from 3 different shops around here.
21, 23.6 and a 25. All of these are basicly the same engine.
I say play with this one and pick up some others too.
Prop hubs and mufflers will all interchange.
These are nice motors with good power.
There are some porting ideas in this forum that will help out a lot.
The best way to go swimming is jump in.
There will always be someone here to give you a hand when needed.
As far as Sq. Inches, what does the manufactor claim?
Have Fun
http://littlewonder.com/12_engine_se...2_pn_385_3.pdf
It's an echo.
I picked up 6 proclaimed dead Echo's from 3 different shops around here.
21, 23.6 and a 25. All of these are basicly the same engine.
I say play with this one and pick up some others too.
Prop hubs and mufflers will all interchange.
These are nice motors with good power.
There are some porting ideas in this forum that will help out a lot.
The best way to go swimming is jump in.
There will always be someone here to give you a hand when needed.
As far as Sq. Inches, what does the manufactor claim?
Have Fun
05-17-2007, 08:35 AM
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RE: Help with Mantis 20 or Echo 21.2
KW,
It looks like a good engine. It spins counter clockwise at the output which is good. I can't really tell how the magnet pickups are arranged. Since the coil isn't mounted on the cylinder, it would be a good canadate for either gas/glow or electronic ignition. Gas/glow would get the weight down so it would work with a smaller plane. The ports on the tiller engines are fairly large, compared with the small trimmers. I would strip it down. Get a hub and glow plug adapter and run gas glow. It should only weigh about 40oz. this way. My Saito 120S weighs 32oz. as an example. Good luck.
Dave
It looks like a good engine. It spins counter clockwise at the output which is good. I can't really tell how the magnet pickups are arranged. Since the coil isn't mounted on the cylinder, it would be a good canadate for either gas/glow or electronic ignition. Gas/glow would get the weight down so it would work with a smaller plane. The ports on the tiller engines are fairly large, compared with the small trimmers. I would strip it down. Get a hub and glow plug adapter and run gas glow. It should only weigh about 40oz. this way. My Saito 120S weighs 32oz. as an example. Good luck.
Dave
05-17-2007, 01:21 PM
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RE: Help with Mantis 20 or Echo 21.2
Ralph and Dave thank you for all the good information. I look forward to converting this engine over. And I'm sure that I will have questions as I go. Again thank you for the information.
Kevin
Kevin
05-26-2007, 08:24 AM
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RE: Help with Mantis 20 or Echo 21.2
Okay I started my conversion of my echo 21.2cc engine. I decided to convert it to a gas/glow engine I cut away most of the unused aluminum on the engine. I have a few questions. On the side of the crankshaft, where the coil used to be (picture 1 sided with the nut and picture 2) can I cut this off so the motor mount won't stick out so far? And the other side (picture 3) is the output side of the crankshaft, it has a hex head screw will this work to hold a prop on and how would I make a prop adapter? Where would be the best place to get a prop adapter, glow plug adapter, muffler and motor mount for this engine? Let me know what you think so far.
Kevin
Kevin
05-26-2007, 09:21 AM
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RE: Help with Mantis 20 or Echo 21.2
Kevin,
You have two choices with the crank shaft on gas/glow. You could make or have made a prop hub that slips over the 10mm rear shaft, using a bolt and washer to retain the prop. Or you could cut the center from the flywheel and install it in its original shaft location. Then purchase a screw on prop hub. The hub would seat firmly with Loctite, against the trimmed down flywheel hub. This would be the easiest way. If you decided to use the slip no hub, it would be helpful to take the engine apart and reverse the crankshaft. The slip on hub could be cut for the key, if desired. I find this fairly eay to do with a swiss file on aluminum. While you had it apart you could trim away the old flywheel housing, making it lighter and more compact. The undrilled flange on the case by the straight shaft would need to be drilled for either direct mounting or a mounting plate. If you decide the take it apart, you can use a Dremel tool with a cutoff disk to remove the unwanted portion of crankshaft. If you cut the shaft with the engine assembled, cover all ports and openings with tape to protect the inside of the engine. Do not allow the shaft temp to rise to much, or you will damage the rear seal and have to replace it. The hole above the exhust port, if it goes through, into the cylinder bore, it should be plugged. This can be done with a screw. It may need to be threaded. I use a 10-32 tap and JB Weld to secure the screw. A 10-32 is a good match for many of the metric bolts used to hold the engine together. My favorite glow plug adapter is a Zenoah, available from Horizon for $9.95.
Dave
You have two choices with the crank shaft on gas/glow. You could make or have made a prop hub that slips over the 10mm rear shaft, using a bolt and washer to retain the prop. Or you could cut the center from the flywheel and install it in its original shaft location. Then purchase a screw on prop hub. The hub would seat firmly with Loctite, against the trimmed down flywheel hub. This would be the easiest way. If you decided to use the slip no hub, it would be helpful to take the engine apart and reverse the crankshaft. The slip on hub could be cut for the key, if desired. I find this fairly eay to do with a swiss file on aluminum. While you had it apart you could trim away the old flywheel housing, making it lighter and more compact. The undrilled flange on the case by the straight shaft would need to be drilled for either direct mounting or a mounting plate. If you decide the take it apart, you can use a Dremel tool with a cutoff disk to remove the unwanted portion of crankshaft. If you cut the shaft with the engine assembled, cover all ports and openings with tape to protect the inside of the engine. Do not allow the shaft temp to rise to much, or you will damage the rear seal and have to replace it. The hole above the exhust port, if it goes through, into the cylinder bore, it should be plugged. This can be done with a screw. It may need to be threaded. I use a 10-32 tap and JB Weld to secure the screw. A 10-32 is a good match for many of the metric bolts used to hold the engine together. My favorite glow plug adapter is a Zenoah, available from Horizon for $9.95.
Dave
