BEAVER DH C2 no 2 30 IN RUBBER DUMAS KIT 306 Nov 25 2025 to PRESENT

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #75

Mon Feb 2 2026

Elastic Tie Downs

More progress.

Pic #1     1244     Right side rear view of the elastic tie downs.

Pic #2     1246     Front right view of the elastics.

Wing Mount

Pic #3     1252     The thin  0.011" cardboard doubler get glued in place with a clamping plate holding it tight to 
B5 where the glue is.   And the  1/16" doubler for the front of B5 is also glued in place.

Pic #4     1253     Here is the result.   Nice and flat and really increasing the strength of B5.

Lastwoodsman
Richard

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #76

Mon Feb 2 2026

Wing Mount

More progress.

Pic #1     1257     The left pilot got knocked off in all of this,   because the Studio Glue Stick did not work.   I sanded up the white pilot's base and the flat of the balsa pedestal,  and used five minute epoxy to glue it back on.

Pic #2     1258     The pilot is glued in,  and the angled Windshield Center Frame Post is now glued in place.

Pic #3     1263     And here is the final fit of the wing left side view.

Pic #4      1267     Right side view of the final wing fit.

Lastwoodsman
Richard

[Lastwoodsman]

BEAVER DH C2  30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER  DUMAS KIT 306

Reply #77

Mon Feb 2 2026

    I think I have almost all of the major hurdles done.  I took everything apart and cleaned the building board.

    Today I worked on the prop hook and nose cone spinner.  The bend of the prop wire had to be snipped shorter a couple of times,  to stop it from interfering with the inside wall of that plastic spinner.
      There was a suspect vibration in the prop spinning trials.    I have the rubber hook of the prop wire,  squeezed into an oval,  whose bend epicenter,  was not in line with the straight wire prop shaft.    I also widened the prop wire hook opening a bit,  while I bent that oval center in line with the prop shaft.  It slides in and out of the Cowl hole for the thrust button bearing,  for ease of prop and motor assembly and dis-assembly. 

Pic #1    1268    Partial Assembly.

Pic #2    1273    Rear rubber tie down.

Pic #3    1274    This pic shows the modern day,  nose down vintage  "jet thrust vectoring" ,  of the three full size shims.

Lastwoodsman
Richard

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #78

Mon Feb 2 2026

       So now I want to make a table top bench stooge to test these motors and the spinner.    I have been trying to sand the tight spinner blade slots,  so that I can squeeze the prop hub base blades,  fully into the spinner,   and stay stuck there,  but to no avail -  as the hub will still want to slip out a little further,  where it won't stay stuck at all while spinning.

Now that I have the fuse disassembled:

Check some flimsy thin clear plastic for a windscreen?
Build a table stooge and test some motor runs,  with and without shims.
Take some assembly pics without the decals.
Glue on all of the decals and logos.
Glue the wing down -  it's ready to glue.
Fit and glue the wing struts.
Glue the landing gear fairings -  recheck that final fit.
Glue on the tail assembly.
Assemble the bush wheels.
Load a rubber motor and check the Center Of Gravity. Balance,  without the spinner,  and with the spinner.
Test glides with 15 - 20  turns on the prop.

Pic #1     1279     Man in the Moon, Full Moonrise at 64 degrees over the building board  5:37 PM  Sun Feb 1 2026.

Pic #2     1286     Work on the prop shaft and spinner.    I had a spare prop to work with also ....

Pic #3     1289     The hook bend is now opened and in line with the prop shaft.

Lastwoodsman
Richard

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #79

Thur Feb 5 2026

Table Top Bench Winding Stooge

     I definitely want to try some stretch winded rubber motors on my new table stooge.

Pic #1     1291     Here I am trying to figure out the best positioning of the walls (ears),   and the wood  2 x 4 ,  with the yellow styrofoam pad as the center fuse support.

Pic #2     1295     Here the holes are drilled in the stooge ear walls for the  3/64"  wire.

Pic #3     1297     View down the fuse.

Pic #4     1299     Here is the final shape using two pads -  the yellow pad,  and a black soft foam  pad cut from a hand/wrist   cushion for a computer mouse.

Lastwoodsman
Richard

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #80

Thur Feb 5 2026

Table Top Bench Winding Stooge

Pic #1     1302     Here the nose cowl and the wing is added.   The cowl must hang past the table edge for the spinning prop.

Pic #2     1306     The pads are sitting at just the right supporting height.   The raised  "hump"  of that mouse pad,   supports the curved uprising rear fuse bottom,  just right.

Pic #3     1309     Here is the good final setup.   The 2 x 4 wood support for the fuse is nailed in place.

Lastwoodsman
Richard

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #81

Thur Feb 5 2026

Table Top Bench Winding Stooge

Pic #1     1311     Top view.

Pic #2     1312     Rear view.

Pic #3     1318     Spinning prop blowing two tissue strips backwards,  weakly,  with the propwash wind.

80 finger winds  =    two rows of knots on the  7" two strand  3/16" rubber motor   =    about seven seconds prop run.

Next is stretch winding some motors ....

Lastwoodsman
Richard

[Marc Guerriero]

Did you enlarge the stab?

[Lastwoodsman]

BEAVER DH C2  30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER  DUMAS KIT 306

Reply #83

Fri Feb 6 2026

Testing Rubber Motors Runs by Stretch Winding with the Table Stooge

Trial #1
    I tried some stretch winds first using a two strand,  3/16"  0.0188",  seven inches long  motor.  Rubber cross section is  0.375"  ( two times 0.0188 ).    It was a lot of good practice switching out motors,  handling the rubber and stretch winding,  while in the stooge,  better than in the field ....   

Stretch winds and run times   
150      =    9 sec            cross section  0.375"
200      =    12 sec
250      =    15 sec
300      =    20 sec
320      =    23 sec

    These two strands of  3/16"  rubber,  0.375" cross section,  really felt way too weak,  and hardly blew the tissue streamers.

------------------------

Trial #2
    So in order to get more  'oooomph' ,  I tried a motor with the two strands of  3/16"  like before,  but with a  two strand  1/8" rubber,  cross section  0.250"  motor also added.    Total cross section now is  0.625"

140    =    7 sec            cross section  0.065"
200    =    9 sec

    This four strand motor,  proved to be too much power.    Really hard to wind in that thick motor ....

------------------------

Trial #3
      So,  I then went with  two strands of  3/16"  ,  but now with two strands of  3/32" rubber added.    Total cross-section is now  0.563".

200    =    8 sec              cross section  0.563"

    And that is all I got done so far.    But,  the  Trial #3  motor of  four strands -  2 of 3/16" and two of  3/32"  -  sure seems to be the motor of choice.

    So,  I should make up a few of those  in  8 1/2"  lengths and with  10" lengths,  but then,  the prop block will pop out on landing (rubber motor is not under tension any more),  .... or will it?

    These results are approximate,  as I lose rubber turns when I take the rubber off of the wire hook,  and try to "thread"  the prop wire hook into the rubber motor end.  I am not using a Crocket hook (diam is 0.42"),  plus ...  -  it then will not fit through the cowl hole of  0.3"  ( thrust bearing diameter).

Pic #1    1320    Three rubber motors to start.

Pic #2    1325    I cannot use these medium size Crocket Hooks.  They are too large for the Cowl hole.

Pic #3    1329    The thrust button is  0.30" diameter and the Thrust Button is 0.42" wide.

Pic #4    1335    I started tying up some fresh motors from the fridge.  Here are four finished motors,  each with four strands (two loops in English), of rubber.  Different lengths,  but all are two strands 3/16"  and  two strands  3/32".

two  7"  ers
one  8 1/2 " er
one  10" er

    The knots are in good position,  and the anchor end of the motor is tied together with a short piece of kite string.  The long kite string at the front gets completely cut off.

End of Reply #83

Lastwoodsman
Richard

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #84

Sat Feb 7 2026

Testing Rubber Motors Runs by Stretch Winding with the Table Stooge

     I tied up a  12"  motor of  2  strands  3/16"  and two strands  3/32".
   
     Today we experimented with long motors.   I got three good runs with the  10"  motor with  13 or 14 second runs on  300  stretch winds.   More testing to come ....

Pic #1     1336     The fuzzy string stretch goes from the hand to the string knot around the front rubber loops of the motor,  then the rubber motor going back to the  1/8"  aluminum tube rear peg motor holder.

Pic #2     1340     I tied up a  10"  motor,  but the string stretch slipped,  and the motor went into the back of the fuse.   I had to use my deep hook motor retriever.

Pic #3     1344     The  10"  motor is installed.   There is a fine  "rattling"   sound when the prop spins.   It is from the 3/16" wire for the rear alum peg tube,  rattling away finely within that alum tube,  with that alum tube wiggling around it,  and hence the drift sideways of the fuse.

Pic #4     1343     10:1  Winder and the  10"  motor.

Lastwoodsman
Richard

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #85

Sat Feb 7 2026

Testing Rubber Motors Runs by Stretch Winding with the Table Stooge

Pic #1     1345     Closeup of the  10:1  Winder.

Pic #2     1346     Now the prop is spinning with enough authority to blow the tissue strips straight back.   The pull is now good for flying,  I think.

Pic #3     1347     Spinning again -  prop is a shadow -  tissue strip is blowing straight back.

Pic #4     1349     I had to tie a small piece of string around the front rubber loops,  because the  3/32"  loop of rubber came off of the prop hook at some point twice in a row.

More to come ....

Lastwoodsman
Richard

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #86

Sun Feb 8 2026

   I made some more motors and did some more testing.

     I got  13 and 14  seconds on 300 stretch winds on a  10"  motor.   

     The best cross section of rubber so far is  0.563' cross section using two strands of 3/16"  and two strands of  3/32".

     Then I tried four strands of  1/8"   0.500' cross section and 250 stretch winds.    The rubber seemed to run off well,  and I got  12,  14,  and 13 seconds.

     I need more testing with the  four strand  1/8" motor.

Pic #1     1351     The screws in the  10:1  Winder were coming loose!   So I tightened them.   I will try to see if the spinner stays on during flight also.

Pic #2     1357     Motors and results so far.

Pic #3     1361     Nose cone stays on.   Good breeze from the  four strand  1/8"  motor,  blowing the tissue strips straight back.

Lastwoodsman
Richard

[calgoddard]

Richard -

I commend you for your methodical building, testing, and posting methods.

If you have any desire to achieve flights longer that 20-30 seconds with your Dumas 30-inch wing span Beaver, then I suggest you consider the following.

Depending on the weight of the finished model, the cross-section of the rubber motor will probably need to be at least 0.75-inches (6 x 1/8-inches), and more likely 1.0-inches (8 x 1/8-inches).

Assuming your Beaver weighs 60 grams, I would start with a 20-gram rubber motor. Because of the relatively short hook-to-peg distance of your Beaver, the motor must be braided to avoid motor bunching and CG shifting. Use a wobbly motor peg.

This larger rubber motor will not fit through the tiny thrust bearing hole in your engine cowling. So the nose of the fuselage of your Beaver would have to be modified to a accommodate the insertion of a nose block, preferably with a 9 1/2-inch Gizmo-Geezer prop assembly. This prop assembly will facilitate easy and precise thrust line adjustments. Use of a Gizmo-Geezer prop assembly may also eliminate the need to braid the rubber motor since it has a built-in spring tensioning mechanism. Maxfliart recently posted a YouTube video showing how he built a balsa frame for receving a nose block inside the plastic cowling of his Guillows Hellcat.

Finally, the small KP winder you have been using is primarily for winding rubber motors on small indoor models. It is too small to comfortably wind a rubber motor with a cross-section of more than around 0.250-inches. You will feel significant torque resistance and the gears of this small KP winder will probably strip sooner, rather than later. Consider purchasing the very exellent 10:1 winder from Volare Products that is pictured below. I have used this winder and find it to be an excellent winder for intermediate size rubber powered free flight models, both scale and sport models.

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #88

Sun Feb 8 2026

Rubber Motors

     I made another motor and did some more testing.

     I made a second  four-strand  1/8"  motor  7"  long,   which gave me   13 sec  and  12 sec  on  250 winds.   This confirms the first four-strand  1/8"  motor which had 12  14  and 13 seconds.    This   0.500"  x section  motor,   seemed to be too weak for flight near the end of the rubber run.

     I changed out the 1/8"  motor  for one of the three  7 inch motors with two strands  3/16"  and two strands  3/32"  rubber,   of  0.563"  x section ,  and  250 winds gave me  13 sec  and  12  sec.      This motor was better because it gave good power throughout the motor run,  and a  little bit more power than the  1/8"  motor.   Plus,  I think the prop wash  'blow'  on the tissue streamers was stronger,  also.    Need to check another one ...

     Tomorrow test a second   7  inch motor with two strands  3/16"   and two strands  3/32"  rubber  of  0.563"  x section  motor,   to confirm the first one,   and then test the  8 1/2"  long motors -  both a new  1/8 four strand,  and the already made,  two strands  3/16"   and two strands  3/32" ,   8 1/2" motors.

Pic #1     1373     Sunrise out the window over the bench.   It has been an unusual deep freeze for a month.

Pic #2     1377     Loaded up holding the prop,  ready to let go.

Pic #3     1380     Tissue strips blowing back.

Pic #4     1381     More prop-wash.

Lastwoodsman
Richard

[Lastwoodsman]

BEAVER DH C2   30 INCH RUBBER POWERED  FREE FLIGHT PARK FLYER   DUMAS KIT 306

Reply #89

Mon Feb 9 2026

Motors

Today,  I tried the last of the  7"  motors 2 strand
3/16    2 strand 3/32 on 250 winds  =  11,   10  sec

Then I tested the  8 1/2"  motor 2 strand
3/16    2 strand 3/32,  on 250 winds,  and on 300 winds.   13 sec,  11 sec  and  14 sec, 15 sec   respectively.

     Then I made a  four strand  1/8"  motor   8 1/2"  long,   tested on 250 winds for 14 sec  11 sec.     Then I upped the winds to   300   and  got  15 sec and 15 sec.

Pic #1     1382     The  8 1/2"  motor at rest,  goes right up to the cowl opening.

Pic #2     1386     While winding,  I position the cowl just ahead of the front of the nose,  where it can spin and "freewheel".

Pic #3     1387     Row of knots.

Pic #4     1389     The wound up cowl is eased back in.

Lastwoodsman
Richard