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 # 360      Tue June 30 2026       post 2 of  7

Flight Report # 27  of  Fri June 26 2026

Pic #1     3670     Short flight soft landing.

Pic #2     3671      Landing near a line showing two heights of grass.

Pic #3     3672     I let the flagging tape fall to the ground,  showing the wind direction.

Pic #4     3673     Moment of landing impact.

Flight 2    25 x 15  =  375  stretch winds.   Nice high flight into the wind  ie.  not much distance traveled.    Pic of the landing.   It is windy.

Lastwoodsman
Richard

[Lastwoodsman]

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

Reply # 361      Tue June 30 2026       post 3 of  7

Flight Report # 27  of  Fri June 26 2026

Pic #1     3674     My set up,   blowing the orange flagging tape.

Pic #2     3675     Big long flight straight out.

Pic #3     3676     Big long flight curves left a little and lands.

Pic #4      3677     That is a long distance from the Pitch.

     A visit came by the Grass Mower Operator  after my second flight.    I was winding the Beaver on the Stooge,  and what do I see in the distance?   The dreaded,  foreboding,  grass mower was approaching      ,  'and the wind began to howl'    .   And he drove right up to me and stopped.   I asked if he could mow another spot first (they have long lists),  since I only had two flights so far.   He said he could but he had to get the Cricket field mowed today.   Then he asked me if the plane was RC (radio controlled).     I said rubber band power,  hoping it would sound like less of a worry.

     So,  it was because of his accommodating me,  that I was able to stay and get the next five flights in,   so I do have to thank him for that.    And now I see that he did get it mowed,  so hopefully all is well.         ie:  I am not getting into trouble yet,   for flying rubber powered balsa plane models in Jackson Park ... all is well ...

Flight 3     27 x 15  405  turns,   4 seconds long low left turn.   I cannot physically crank in any more turns without breaking the  15:1  winder -  I already broke the  10:1  winder dong the same thing.

Lastwoodsman
Richard

[Lastwoodsman]

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

Reply # 362      Tue June 30 2026       post 4 of  7

Flight Report # 27  of  Fri June 26 2026

Pic #1     3679     Flight 4   long flight  11 sec

Pic #2     3680     Flight 5   long flight  13  sec 

Pic #3     3681     Landing of perfect  13  sec flight.

Pic #4     3682     Flight  6   8 sec  perfect

Flight  4  and  5  were both very long flights of  11 seconds and  13  seconds,  respectively,  on the  13"  motor.   These tied the  12"  motor best flights.

Flight 4   405 turns  11 seconds !!.     This flight was launched from the pitch and landed way out,  right beside the outer boundary white paint stripe on the Cricket Field grass.

     I launched on an upward angle,  straight into and at right angles,  to the tree line.   The wind was coming from the left,  and kept the plane flying straight  (it turns left naturally) off the start.   It eventually started to turn left into the wind (little wind).   Once the plane entered close to the lee wind side of the trees,  where the wind was blocked off,  it had enough rubber run out,  for a long lazy slow finish,  right out to the stripe.    All factors must came together to get this long of a flight -  especially the direction of launch,  and the angle of attack at launch., and the wind.   No super records or anything like that  -  just some fun small park flying.

Lastwoodsman
Richard

[Lastwoodsman]

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

Reply # 363      Tue June 30 2026       post 5 of  7

Flight Report # 27  of  Fri June 26 2026

Pic #1     3683     Landing of  Flight 6.   Look at that thick grass !

Pic #2     3684     Underside view and closeup of the long grass.

Pic #3     3685     Here is my set up by the Pitch.

Pic #4     3687     Flight  7     It went right !!  Oh no!

Flight  5    405  turns  13 seconds !!   This ties the 12" motor record.   It was almost  2/3  of a circle,  and was the same flight as Flight 4,  but further out left.

      These last two flights 4 and 5,  really completely ran out the end of the rubber motor knots,  to the softest of landings in the unusually high grass.

Lastwoodsman
Richard

[Spiros]

I can hardly imagine this beauty, flying only for 13".

Why is this happening? Have you tried a straight single rubber? Obviously shorter but definitely could be stronger in my opinion.

[Lastwoodsman]

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

Reply # 365      Tue June 30 2026      post 6 of  7

Flight Report # 27  of  Fri June 26 2026

Pic #1    3689    Wind gust blowing the flagging tape.  Time to go.

Pic #2    3690    Last pic of the high grass before mowing.

Pic #3    3691    Even deeper grass.

Pic #4      3692    The flower garden is fully planted.

Flight  6    405  winds  8 sec  perfect flight.  It went out one quarter circle left,  but not as far as the  13  and  11  second flights.  Good flight nonetheless.

Flight  7  405    6 sec    bad launch pointing too far to the right,  and the wind caught it and sent it way right to my shock!  The gusts were getting more prominent,  and it was getting windier, and it was too hot.  So I quit while I was ahead.

Lastwoodsman
Richard

[Lastwoodsman]

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

Reply # 366      Tue June 30 2026      post 7 of  7

Flight Report # 27  of  Fri June 26 2026

Pic #1    3693    Wind on the flag on the way out.

Pic #2    3724    pics of Beaver at home

Pic #3    3726    The  9 inch tight motor is back inside the Beaver,  resting ....

Pic #4    3727    Ready to fly finger winds again .

    It might be later in the fall,  here as well,  for the next flights,  as we are in the big summer heat wave now ...

Conclusion:  The  13"  motor appears to be as good as the  12"  motor,  and the  15"  motor was too sluggish.  Of course we need more flights to be sure.    But for now,  that is the end  ....

End of Flight Report  #27 of  Fri June 26 2026

Lastwoodsman
Richard

[Lastwoodsman]

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

Reply # 367     

Wed July 1 2026

Hi Spiros!  Thanks for the  'likes'.   

Quote from Spiros above  " I can hardly imagine this beauty, flying only for 13".

"Why is this happening? Have you tried a straight single rubber? Obviously shorter but definitely could be stronger in my opinion.  "

    That is a good  question,  the all time  question ... .    I was only going for a ten second flight from the beginning.  I think ZKAUD Mike said that he would be satisfied with a ten second flight (where is Mike?).  So,  I was going with that.
      I documented,  first time for me,  the different rubber motors and cross sections and their builds,  and their run times on my handy dandy table stooge,  and the run times outside also.    A power run time of 12 sec on the table stooge,  does not equate to a  12  sec flight outside ...

Pic #1    1739
Pic #2    2695
Pic #3    2726
Pic #4    2859   

"straight single rubber?"  -  do you mean a single strand  ( one half of a loop ),  and what total width cross-section of the rubber strand(s),  of your straight single rubber ?    I found that the best  'pull'  was that  eight strand  motor  of total cross section of  0.813" of rubber motor strands.    Since there is not a  0.813"  width in rubber  (only  3/32",  1/8",  and  3/16"),  I added extra strands sizes of rubber and tested them as I went along.

      I started this rubber powered hobby 14 years ago at age 55,  with the Guillow  Nieuprt 11  24" laser cut kit (totally hooked) just for a display model back then,  so I don't have all the answers.    I think it was Cal Goddard who said it would be good to get a ten second flight with this 30" Beaver plane too.  And I always thought that that blunt nose,  and the enlarged landing gear and no windshield,  were all resistance factors causing shorter flights.

PLUS

Total Wing Area  3.3125" x 30"  =  99.375" sq

Max Weight Rule for Flying is  0.5 g of model weight per one sq inch of lifting surface.

99.375 in sq  X  0.5g per in sq =  49.7 g

The Beaver weighs about 113 g,  so it is way over weight.   

    I am settling in for  'build mode' with the 30" Gipsy Moth now,  in my air-conditioned apartment,  during this heatwave.    No flying for me ...

Lastwoodsman
Richard

[Spiros]

What I would do, is double strand double lenght than the motor to peg. I'm not sure on the size but in metrics I would go somewhere betweem 4,20 - 4,40mm.

[Lastwoodsman]

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

Reply # 369        Friday July 10 2026

Beaver flight Report #28 of  Fri July 10 2026

180 finger winds  10 flights  9 sec  9 sec  8 sec couple of fours and five secs  Some launches were way too horizontal.    My long flights were,  I'm guessing,  launched at about 30 to 40 degrees up from horizontal,  maybe more.  I must concentrate on the launch more .... 

    Broken strand,  almost no wind,  they did mow the grass.  Not many pics today,  but some good flying.

    There was almost no wind.  They did mow the grass earlier in the day.  After about 10 flights,  I could tell there was a broken strand of rubber in there,  took a look and saw it,  and quit.    Getting very hot and muggy.

    My first flight was into the wind by the edge of the field.  It went nowhere forward into the air and dropped to the ground,  nice landing, after 4 seconds.  I was going to quit because I thought it was too windy.  Then I moved to the Pitch,  and,  with the wind coming from the left,  I launched straight ahead,  the plane goes straight (it always goes left) because of the wind,  then the plane turns into the wind for a long slow final finish.

    I moved to the Pitch,  and a guy shows up to watch,  and man,  a nine second flight!    And he got to see it.

    The four or five long flights were the most entertaining.    One launch pointed way too high.  Off it flew to the highest I ever saw it,  stalled and came down.  I was begging for it to recover,  and it slowly started to, more and more,  and finally to a long low final ground level flight to a soft landing.  Now that is a close call -  good thing that the stall started at high altitude,  which made for a nice big long swoop.

Pic #1    3886    Flowers at the Entrance to Jackson Park.

Pic #2    3887    The Cricket Field just got cut this morning.

Pic #3    3888    The only in flight pic -  launched too much horizontally.

Pic #4    3891    The cut grass is still deep and green on this side of the Cricket Field.

    Suggestion from Spiros    (and liked by John Ozpaf    ) :  " double strand double length than the motor to peg. I'm not sure on the size but in metrics I would go somewhere between 4,20 - 4,40mm."

    I don't know what that means (we here in Canada,  are still part of the British Commonwealth)  -  double strand  -  from what to what,  starting at what?

    "double length than the motor to peg" -  you mean double the prop hook to rear motor peg distance,  rubber motor length?

    OK here is my take.  My prop hook to rear peg is 10 inches.  The best motors I found were  12"  and 13"  rubber motors stretch 405 winds wound on a stooge  (9, 10, 12 sec flights).  I already tried a  one and one half times the prop hook to rear peg motor,  15" motor,  and found it to be too sluggish with all that extra motor weight,  and never running out the wound motor knots.

    But today,  I got two 9 second fights on  180  finger winds    using a tight 9 inch motor,  and running out all of the motor at landing.

    I think that that 20 inch motor you are suggesting,  will add too much weight to the already  over weight Beaver of  113 grams ( including the tight 9 inch motor). 

Lastwoodsman
Richard

[Jmk89]

Richard

4.0 mm is about 5/64", so Spiros' suggestion is for a "fat" 5/64" or a "thin" 3/16" strand. With the double length concept, I think Spiros envisages braiding the motor since double length unbraided would likely have slack rubber floating around inside the fuselage altering trim all the time. So I assume that it would be a four strand motor. 

My recollection is that the midpoint between prop hook and rear peg for the Beaver is pretty much under the Centre of Gravity, so while the weight may go up with a bigger motor, the trim should remain about the same ( except that the glide may be a bit faster) and you will have a significantly longer motor run. All up, it might be worth trying.  One advantage is that you would not need to go anywhere near maximum winds to get adequate power and that is likely to reduce likelihood of strand breaks, so long as the motor is kept well lubed

[Spiros]

Please do excuse my English. Sometimes it's really bad.

So to explain a bit what I meant.

Assuming the distance between motor peg and rear peg is 15cm, the first strand is 30cm.

Then you just add another 30cm (overall length of the rubber 60cm) and you make a loop (double strand) of 30cm.

It is indeed not very convenient when loose, however it will take more turns and will give more power at the beginning of the flight.

I would try it this way too. Lst year my Piper Pawnee flew only with this method. Otherwise, would not get off the ground.......

[Lastwoodsman]

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

Reply # 372         Saturday July 11 2026

Re:   Beaver flight Report #28 of  Fri July 10 2026

     Well,  thanks a lot for all your replies,  interest, and
suggestions.   I know you all mean well,  and I will keep them in mind.   I am just running out of energy to get a couple of more seconds of flight times,  by experimenting with long stretch wound motors.   I am quite content just to fly finger winds for now.

     I have already beaten this Beaver to death with different rubber motors and flight reports,  trying for maximum  flight times.    I am not sacrificing any more time and effort making eight strand long motors of rubber,   for the Beaver.     I am saving that rubber for the up and coming,  30"  Gipsy Moth Biplane,  which has a new,  extra prop hook to rear peg,  of  8 inches,   while still incorporating the  original plan/kit,   prop hook to rear peg of  12.75  inches ,   both with separate rear peg plates,  all ready to go,  and already installed on the fuse side frames ....

     And here is the confidence booster -   a check on my rubber supply,   reveals a more than adequate,  over abundance of,    3/32"  {2.382 mm},   4/32"  (1/8")  {3.175 mm},   and  6/32" (3/16")  {4.763 mm},    rubber!    So no worries there!    Onwards.   Long live the core.      Rock the category.

Pic #1     3937     Rubber Supply

Lastwoodsman
Richard

[Lastwoodsman]

Sun July 12 2026       Reply #373 

      After making all those motors,  we did shoot out to see what the grass was like,  after that rubber motor preamble.

Flight Report #29  of  Sunday July 12 2026

     Well,  we left the apt. at  8:00 PM.  By the time we got to the Cricket Field,  the players had just walked off after playing in the heat all day.   And the sun had set low enough to cover my half of the flying field in shade,  for both winding and flying.    Four flights of 7, 6, 5, and 4  seconds,  all on 180 winds with the  biggest  0.938"   motor.   And the grass was still very good.

     No pics as I brought the camera,  but I forgot the disc in the computer.    The humidity was bearable at only  41 %,  but the heat warning is real.    You can tell when you  get back in the apartment air conditioning.

     We will see what happens tomorrow morning.

     All in all,  the Beaver flies well with the  strongest 0.938"  motor also,  maybe not as long time wise,  but running out the rubber OK.   

End of Flight Report #29  of  Sunday July 12 2026.

Lastwoodsman
Richard

[Lastwoodsman]

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

Reply #374       Tuesday July 14 2026     post 1  of  8

Beaver Flight Report  #30  of  Mon July 13 2026

     Well we did get out first thing in the morning.   We left the apt at  8:00 AM with the Beaver with the new powerful  strongest 0.938"  motor,   RTF.

     We got in 7 flights,  the last four of which,  were with a broken strand of rubber.    We got back home at  9:10 AM after some leisurely pics after the flight times of  7,  5,  5,  6,  7,  6,  6  seconds.    The weather was sunny,   79 deg F (feels like 89 deg F),  54 % humidity,  with winds from  the WSW at 4 mph, gusting to 7 mph.

Seven Flights of   7,  5,  6,  6,  7,  6,  6  seconds


Start of Walk Out to the Field

     There was very little wind to begin with.   I got to wind the motor and cast the Beaver,  from the shade of the trees on the South end of the Park.   All flights were  180  or  200 finger winds.  The wind was coming from the south,  and perpendicular to the straight treeline shade,  that I was launching from.    I launched straight along with the wind,  which was blowing Northwards.    I launched in the calm air that was blocked by the tree line,  and got some nice high and long flights,  all downwind.

Pics on the walk in

Pic #1     3969     The grass was full of dew.
Pic #2     3970     I went back for the 'wind on the flag' pic at the Jackson park entrance.
Pic #3     3971     Big construction.   The Cricket Field is in the background.   No one is on the field at 8:15 AM on a Monday.
Pic #4     3972     Long morning shadows on the field.   The grass has not been cut.

Lastwoodsman
Richard
cont