Bruce Cronkhite
Jun 01, 1996, 01:00 AM
<html>
<head>
<title>How To Convert the Climmax HLG to E Power</title>
</head>
<body bgcolor="#FFFFFF">
<h3>Introduction </h3>
<p>One of the more popular R/C hand launched gliders is the Climmax by CR Aircraft.
Charlie Richardson (CR) has converted one of them to electric power with a direct drive
Speed 400 but he was not real pleased with the performance, for whatever reason. I decided
to undertake a conversion of the airplane for a Speed 400 with gear reduction to see if
the performance couldn't make Charlie happier. It is possible that the size of the Climmax
(400 sq. in.) contributed to the lower performance of the direct drive, but would really
work well with the gear. </p>
<p>There are many ways to gear a Speed 400, but regardless of the type of gear used, the
larger prop you can use requires a spinner of about 1.5 inches DIA. I decided to go with
the Graupner 1703 type with the 2.33:1 gearing. Also, I decided to use the GR1703/1
Firewall mount, to stay within the spinner diameter. Secondly, an installation for this
setup will work with the 4:1 planetary in-line box, although I haven't tried this box yet
because of cost. If the airplane works out well. then the investment may be justified to
use the larger prop possible with the lower gear ratio. </p>
<p>Basically this modification consists simply of making the fuselage wider to accept the
geared Speed 400. The excellent aerodynamic design of the Climmax is untouched. The
details of the modification described here are intended to make the conversion as easy and
foolproof as possible. It would be a lot easier if we had plans, but that's why the
instructions are so detailed. </p>
<h3>What You Will Need </h3>
<p><nl> </p>
<p>A CR Aircraft Climmax wood kit. CR Aircraft 205 Camille Way Vista, CA 92083 Tel. (619)
630-8775 </p>
<p>Geared Speed 400 with 1703 gearbox and firewall mount as described above </p>
<p>One piece of 3/8 x 2 x 10 inch balsa - new top hatch </p>
<p>1/8 in. light ply for bulkheads - about 1/2 sq.ft is more than enough. Also a small
piece of birch 1/8 in. ply for new wing mount plates </p>
<p>1/8 in. sheet - for the bottom sheet from the spinner to the wing L.E. Make this firm
stuff </p>
<p>3/8 in triangle stock - about 8 in. long </p>
<p>Med. Fibreglass - K & B or other with finishing epoxy </p>
<p>Normal modelling stuff for cutting and glueing and whatever else you normally do. </p>
<p>Propeller and spinner of your choice </nl> </p>
<h3>What You Do. </h3>
<p>Proceed to build the kit just like the instructions tell you. Charlie starts with the
wing. His method of sheeting a foam wing is as good as any, and better than most. </p>
<p>The only departure from the wing instructions is to build the polyhedral wing -not the
aileron wing- and put only half the dihedral called for in the plans. That is, cut each
dihedral dimension on the plans in half. This is not my idea, it's Charlie's. He says that
his aileron Climmax flies just fine with rudder only, so that dihedral is wasted. </p>
<p>By the way, the Climmax wing cores are cut with washout in the tip panels which is also
good for electric. </p>
<h3>Modifying the fuselage </h3>
<p>The fuselage is built almost exactly the same as the original kit except that it is
widened to allow use of a 1-1/2 in. spinner. The spinner that you get for your prop may be
1-1/2, 1-9/16 or 1-5/8 depending on the prop or manufacturer you buy. It makes little
difference which because you just have to fudge the diameter of the nose circle to suit. I
made mine 1-5/8 because I could then cut it down as required. </p>
<p>Start building the fuselage just as the instructions say. The first thing to do is
epoxy on the 1/64 ply doublers. The problem is that Charlie doesn't include the ply
anymore because of cost. That's O.K. because you can use a cheaper, lighter material:
linen based tracing paper or vellum. I learned about this from Salient Designs Boxer
series of gas powered pattern models. It's what they use for doublers. </p>
<p>If you don't have any vellum, go to your nearest blueprint shop and ask them to tear
off a foot from the roll for you. Epoxy the vellum to the sides just as the instructions
say to do with the plywood. </p>
<p>Now add the 1/8 sq. sticks to the sides, but leave off the front verticals. </p>
<p>Cut four pieces of 3/8 triangle 2 in. long. Glue these to the sides up against the 1/8
sq. at the front of the sides, after sanding off the bottom of the tri stock to fit the
bottom curve. Leave the tri stock full depth at the front, and sand off the rear because
you need the height at the front. These should be glued on at least even with the front
edge of the fuse side, and when the glue is dry sand the tri stock off to be flush with
the front edge of the side. Got that? </p>
<p>Now cut little pieces of 1/8 sq. with diagonal ends to fill in between the tri stock
along the fuse front edge. </p>
<p>Now glue on the pushrod housings as it says, except put the rudder housing on the left
side and the elevator housing on the right side. Put both of them at the same height as
the elevator housing is shown. </p>
<p>By the way again, I use 1/32 wire for the pushrods instead of cable. Put the wire in
the rudder housing while you mount it. That way it will keep you from bending the housing
too much. </p>
<p>Now make a new fuselage bulkhead out of lite ply. It should be 1-7/16 wide, and as high
as the fuselage side at the front end of the wing cutout: at the notch. It should have a
1/8 sq. notch at both bottom corners, and a 1/8 x 1/4 notch at each top corner, with the
1/4 in. dimension vertical. Also, cut a hole near the bottom of the bulkhead to feed the
battery wires through. </p>
<p>Glue the bulkhead to one fuselage inside, exactly 90 deg. to the side, at the wing
cutout notch, and vertical. </p>
<p>Cut two pieces of 1/8 sq. exactly 1-3/16 long. Lay the second side on the top of the
bulkhead with the tail blocked up to be level. Glue the two 1/8 sq. pieces between the
extreme front ends of the 1/8 sq. fuselage side stiffeners. The front end should now be
exactly rectangular, not square, but rectangular. The two new pieces of 1/8 sq. should lay
up against the bottom side of the tri stock at the front. Now glue the fuselage side, that
you laid on top, to the bulkhead. </p>
<p>Be carefull with that last step. If everything isn't orthogonal your fuselsge will look
funny. Don't forget to make sure that the tail ends of the fuse sides line up too, while
you're doing all that. </p>
<p>When the glue is really dry, check the line up of everything. You should be able to
pull the fuselage tail ends together straight. If you can't do that, crack enough joints
to straighten it out, then glue it back, and this time tack glue the tail ends togather
making sure that the fuselage is straight from nose to tail. </p>
<p>Now fill in the space between the 1/8 sq. bottom rails next to the 3/8 tri stock with
1/8 sheet. Also fill in the same area on the top side, but only for 1/2 in. back from the
front 1/8 cross stick. </p>
<p>Now saw everything that is non-essential away from the gearbox. That includes both the
bearer mounting lugs and the artistic looking stiffener over the motor. You can cut that
off about 1/4 in. behind the gearbox-to-motor mounting surface clear across the gearbox.
You aren't going to use those mounts, so why carry the weight, and you need to cut off the
bearers to make it fit in the fuselage. </p>
<p>Now assemble the motor to the gearbox, and the mounting plate to the gearbox with the
long screws supplied with the mount. You may have to ream out the holes in the plate a
little. </p>
<p>Cut a piece of lite ply into a circle 1-5/8 DIA or the diameter of the spinner you
have. Drill a hole that is a push fit for the propellor shaft in the center of this piece
of board. Push the shaft through the board until the mount plate is flush. Then mark, and
drill, the two holes for the screws that mount the mount (grin) to the firewall.
Countersink those two holes, soak them with CA to harden the lite ply, and mount the whole
mess to the plate. </p>
<p>Now comes the fitting and carving and sanding to make the motor assembly fit in the
fuselage. The circular plastic mount has to fit inside the 1/8 sq. horizontal and vertical
front end pieces. Some of them will have to be sanded away in the middle. The motor goes
on the upper side of the assembly so you can make room for it by gouging out the top
block. There isn't enough room on the bottom. Make sure that you have the motor shaft
centerred in the fuselage before you quit. You can see how much meat you have removed from
each side to get the mount plate in, and this should give you a good idea of where you
are. </p>
<p>Start by trying to insert the motor assembly in from the front. A large rattail file
works well here. Once you get it started you will find that you have to relieve the
insides of the upper tri stock for the motor to fit up through them. Just keep on fittin'
and fussin' until all of a sudden, it drops in. Making sure everythng is centered, mark
where the plywood disk is on the front of the fuselage. </p>
<p>Now remove the disk from the mount/gearbox/motor and epoxy the disk to the front of the
fuselage where you marked it. It should be just even on both sides and overhang 1/8 in. on
the bottom; it should also overhang at the top. </p>
<p>Just for grins, now test fit the motor/gearbox/mount assembly back into the fuselage up
against the rear of the plywood plate. If it doesn't fit now, fix it, because it will not
be possible later. </p>
<h3>Home Stretch </h3>
<p>Sheet the bottom of the fuselage (after removing the motor assembly) with 1/8 sheet
from the front plate back to the fuselage bulkhead, with 3/32 sheet under the wing, and
1/16 from there back to the tail, all cross grain. Bevel the front end of ther hatch block
to fit against the rear of the front plate and cut it off to the length shown on the plans
over the top of the wing. You will cut it later into the front top block and the hatch. </p>
<p>Cover the top behind the wing with cross grain 1/16. You can put the 1/8 sq. crosspiece
at the wing T.E. location in now. The original Climmax bulkhead and finger hole is
dispensed with. </p>
<p>As a last gimmick, tack glue your spinner to the front plate over a 1/16 in. sheet
spacer. This will serve as a shaping guide; cover the spinner with masking tape if you are
nervous about scraping it. </p>
<p>Now shape the fuselage with knife and sanding things until you have a nice flow from
the spinner back. There is enough meat in the front corners to give a nice smooth contour.
</p>
<p>When the shaping is done, pop the hatch off and cut off the front of it with a razor
saw at the rear of the motor location. Remount the motor assembly and remove balsa from
the underside of the front top block to clear the top of the motor. Then glue the top
block back on. </p>
<p>You're done with the conversion. </p>
<p>My electric equipment lineup is: fuse under the rear of the motor; Lofty Persuits BEC
controller crosswise behind the motor; Hitec/RCD Micro 535 Receiver behind that; and the
two servos just in front of the bulkhead. The battery pack is 7-500AR's. </p>
<p>I glued two pieces of 3/16 sheet to the fuselage sides just in front of the bulkhead,
and used Trinity servo mounting tape to attach the servos. Smear slow CA on the balsa
befor sticking on the tape and it will never come off. With the sticky tape mount you can
put the servos at the right height for the pushrods so they slide easy. </p>
<p>Now finish the airplane as per the kit instructions. Make it some really visible color,
at least on the bottom. Have fun. </p>
<p>This document may be distributed freely. My email is <a href="http://rcgroups.com/shared/nospam.php?u=minton&d=worldnet.att.net">minton(at)worldnet.att.net</a> </p>
<p>Bruce Cronkhite
</body>
</html>
<head>
<title>How To Convert the Climmax HLG to E Power</title>
</head>
<body bgcolor="#FFFFFF">
<h3>Introduction </h3>
<p>One of the more popular R/C hand launched gliders is the Climmax by CR Aircraft.
Charlie Richardson (CR) has converted one of them to electric power with a direct drive
Speed 400 but he was not real pleased with the performance, for whatever reason. I decided
to undertake a conversion of the airplane for a Speed 400 with gear reduction to see if
the performance couldn't make Charlie happier. It is possible that the size of the Climmax
(400 sq. in.) contributed to the lower performance of the direct drive, but would really
work well with the gear. </p>
<p>There are many ways to gear a Speed 400, but regardless of the type of gear used, the
larger prop you can use requires a spinner of about 1.5 inches DIA. I decided to go with
the Graupner 1703 type with the 2.33:1 gearing. Also, I decided to use the GR1703/1
Firewall mount, to stay within the spinner diameter. Secondly, an installation for this
setup will work with the 4:1 planetary in-line box, although I haven't tried this box yet
because of cost. If the airplane works out well. then the investment may be justified to
use the larger prop possible with the lower gear ratio. </p>
<p>Basically this modification consists simply of making the fuselage wider to accept the
geared Speed 400. The excellent aerodynamic design of the Climmax is untouched. The
details of the modification described here are intended to make the conversion as easy and
foolproof as possible. It would be a lot easier if we had plans, but that's why the
instructions are so detailed. </p>
<h3>What You Will Need </h3>
<p><nl> </p>
<p>A CR Aircraft Climmax wood kit. CR Aircraft 205 Camille Way Vista, CA 92083 Tel. (619)
630-8775 </p>
<p>Geared Speed 400 with 1703 gearbox and firewall mount as described above </p>
<p>One piece of 3/8 x 2 x 10 inch balsa - new top hatch </p>
<p>1/8 in. light ply for bulkheads - about 1/2 sq.ft is more than enough. Also a small
piece of birch 1/8 in. ply for new wing mount plates </p>
<p>1/8 in. sheet - for the bottom sheet from the spinner to the wing L.E. Make this firm
stuff </p>
<p>3/8 in triangle stock - about 8 in. long </p>
<p>Med. Fibreglass - K & B or other with finishing epoxy </p>
<p>Normal modelling stuff for cutting and glueing and whatever else you normally do. </p>
<p>Propeller and spinner of your choice </nl> </p>
<h3>What You Do. </h3>
<p>Proceed to build the kit just like the instructions tell you. Charlie starts with the
wing. His method of sheeting a foam wing is as good as any, and better than most. </p>
<p>The only departure from the wing instructions is to build the polyhedral wing -not the
aileron wing- and put only half the dihedral called for in the plans. That is, cut each
dihedral dimension on the plans in half. This is not my idea, it's Charlie's. He says that
his aileron Climmax flies just fine with rudder only, so that dihedral is wasted. </p>
<p>By the way, the Climmax wing cores are cut with washout in the tip panels which is also
good for electric. </p>
<h3>Modifying the fuselage </h3>
<p>The fuselage is built almost exactly the same as the original kit except that it is
widened to allow use of a 1-1/2 in. spinner. The spinner that you get for your prop may be
1-1/2, 1-9/16 or 1-5/8 depending on the prop or manufacturer you buy. It makes little
difference which because you just have to fudge the diameter of the nose circle to suit. I
made mine 1-5/8 because I could then cut it down as required. </p>
<p>Start building the fuselage just as the instructions say. The first thing to do is
epoxy on the 1/64 ply doublers. The problem is that Charlie doesn't include the ply
anymore because of cost. That's O.K. because you can use a cheaper, lighter material:
linen based tracing paper or vellum. I learned about this from Salient Designs Boxer
series of gas powered pattern models. It's what they use for doublers. </p>
<p>If you don't have any vellum, go to your nearest blueprint shop and ask them to tear
off a foot from the roll for you. Epoxy the vellum to the sides just as the instructions
say to do with the plywood. </p>
<p>Now add the 1/8 sq. sticks to the sides, but leave off the front verticals. </p>
<p>Cut four pieces of 3/8 triangle 2 in. long. Glue these to the sides up against the 1/8
sq. at the front of the sides, after sanding off the bottom of the tri stock to fit the
bottom curve. Leave the tri stock full depth at the front, and sand off the rear because
you need the height at the front. These should be glued on at least even with the front
edge of the fuse side, and when the glue is dry sand the tri stock off to be flush with
the front edge of the side. Got that? </p>
<p>Now cut little pieces of 1/8 sq. with diagonal ends to fill in between the tri stock
along the fuse front edge. </p>
<p>Now glue on the pushrod housings as it says, except put the rudder housing on the left
side and the elevator housing on the right side. Put both of them at the same height as
the elevator housing is shown. </p>
<p>By the way again, I use 1/32 wire for the pushrods instead of cable. Put the wire in
the rudder housing while you mount it. That way it will keep you from bending the housing
too much. </p>
<p>Now make a new fuselage bulkhead out of lite ply. It should be 1-7/16 wide, and as high
as the fuselage side at the front end of the wing cutout: at the notch. It should have a
1/8 sq. notch at both bottom corners, and a 1/8 x 1/4 notch at each top corner, with the
1/4 in. dimension vertical. Also, cut a hole near the bottom of the bulkhead to feed the
battery wires through. </p>
<p>Glue the bulkhead to one fuselage inside, exactly 90 deg. to the side, at the wing
cutout notch, and vertical. </p>
<p>Cut two pieces of 1/8 sq. exactly 1-3/16 long. Lay the second side on the top of the
bulkhead with the tail blocked up to be level. Glue the two 1/8 sq. pieces between the
extreme front ends of the 1/8 sq. fuselage side stiffeners. The front end should now be
exactly rectangular, not square, but rectangular. The two new pieces of 1/8 sq. should lay
up against the bottom side of the tri stock at the front. Now glue the fuselage side, that
you laid on top, to the bulkhead. </p>
<p>Be carefull with that last step. If everything isn't orthogonal your fuselsge will look
funny. Don't forget to make sure that the tail ends of the fuse sides line up too, while
you're doing all that. </p>
<p>When the glue is really dry, check the line up of everything. You should be able to
pull the fuselage tail ends together straight. If you can't do that, crack enough joints
to straighten it out, then glue it back, and this time tack glue the tail ends togather
making sure that the fuselage is straight from nose to tail. </p>
<p>Now fill in the space between the 1/8 sq. bottom rails next to the 3/8 tri stock with
1/8 sheet. Also fill in the same area on the top side, but only for 1/2 in. back from the
front 1/8 cross stick. </p>
<p>Now saw everything that is non-essential away from the gearbox. That includes both the
bearer mounting lugs and the artistic looking stiffener over the motor. You can cut that
off about 1/4 in. behind the gearbox-to-motor mounting surface clear across the gearbox.
You aren't going to use those mounts, so why carry the weight, and you need to cut off the
bearers to make it fit in the fuselage. </p>
<p>Now assemble the motor to the gearbox, and the mounting plate to the gearbox with the
long screws supplied with the mount. You may have to ream out the holes in the plate a
little. </p>
<p>Cut a piece of lite ply into a circle 1-5/8 DIA or the diameter of the spinner you
have. Drill a hole that is a push fit for the propellor shaft in the center of this piece
of board. Push the shaft through the board until the mount plate is flush. Then mark, and
drill, the two holes for the screws that mount the mount (grin) to the firewall.
Countersink those two holes, soak them with CA to harden the lite ply, and mount the whole
mess to the plate. </p>
<p>Now comes the fitting and carving and sanding to make the motor assembly fit in the
fuselage. The circular plastic mount has to fit inside the 1/8 sq. horizontal and vertical
front end pieces. Some of them will have to be sanded away in the middle. The motor goes
on the upper side of the assembly so you can make room for it by gouging out the top
block. There isn't enough room on the bottom. Make sure that you have the motor shaft
centerred in the fuselage before you quit. You can see how much meat you have removed from
each side to get the mount plate in, and this should give you a good idea of where you
are. </p>
<p>Start by trying to insert the motor assembly in from the front. A large rattail file
works well here. Once you get it started you will find that you have to relieve the
insides of the upper tri stock for the motor to fit up through them. Just keep on fittin'
and fussin' until all of a sudden, it drops in. Making sure everythng is centered, mark
where the plywood disk is on the front of the fuselage. </p>
<p>Now remove the disk from the mount/gearbox/motor and epoxy the disk to the front of the
fuselage where you marked it. It should be just even on both sides and overhang 1/8 in. on
the bottom; it should also overhang at the top. </p>
<p>Just for grins, now test fit the motor/gearbox/mount assembly back into the fuselage up
against the rear of the plywood plate. If it doesn't fit now, fix it, because it will not
be possible later. </p>
<h3>Home Stretch </h3>
<p>Sheet the bottom of the fuselage (after removing the motor assembly) with 1/8 sheet
from the front plate back to the fuselage bulkhead, with 3/32 sheet under the wing, and
1/16 from there back to the tail, all cross grain. Bevel the front end of ther hatch block
to fit against the rear of the front plate and cut it off to the length shown on the plans
over the top of the wing. You will cut it later into the front top block and the hatch. </p>
<p>Cover the top behind the wing with cross grain 1/16. You can put the 1/8 sq. crosspiece
at the wing T.E. location in now. The original Climmax bulkhead and finger hole is
dispensed with. </p>
<p>As a last gimmick, tack glue your spinner to the front plate over a 1/16 in. sheet
spacer. This will serve as a shaping guide; cover the spinner with masking tape if you are
nervous about scraping it. </p>
<p>Now shape the fuselage with knife and sanding things until you have a nice flow from
the spinner back. There is enough meat in the front corners to give a nice smooth contour.
</p>
<p>When the shaping is done, pop the hatch off and cut off the front of it with a razor
saw at the rear of the motor location. Remount the motor assembly and remove balsa from
the underside of the front top block to clear the top of the motor. Then glue the top
block back on. </p>
<p>You're done with the conversion. </p>
<p>My electric equipment lineup is: fuse under the rear of the motor; Lofty Persuits BEC
controller crosswise behind the motor; Hitec/RCD Micro 535 Receiver behind that; and the
two servos just in front of the bulkhead. The battery pack is 7-500AR's. </p>
<p>I glued two pieces of 3/16 sheet to the fuselage sides just in front of the bulkhead,
and used Trinity servo mounting tape to attach the servos. Smear slow CA on the balsa
befor sticking on the tape and it will never come off. With the sticky tape mount you can
put the servos at the right height for the pushrods so they slide easy. </p>
<p>Now finish the airplane as per the kit instructions. Make it some really visible color,
at least on the bottom. Have fun. </p>
<p>This document may be distributed freely. My email is <a href="http://rcgroups.com/shared/nospam.php?u=minton&d=worldnet.att.net">minton(at)worldnet.att.net</a> </p>
<p>Bruce Cronkhite
</body>
</html>