HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Oct 08, 2012, 07:21 PM
Registered User
rcflyinff's Avatar
United States, FL
Joined Mar 2012
563 Posts
Quote:
Originally Posted by BAF23 View Post
I fly the Belgian colored one with the Mrrcsound system (article and pictures somewhere on previous pages). Having read the thread before building, I installed tail wheel steering because I only fly on a tarmac surface, and more for the sake of good looks changed into dubro wheels all around. Tailwheel was no problem to replace, but I had to drill out the mainwheel axis. I initially replaced those with plastic ones but after a few landings they cracked, leading to a prop hitting the surface and bending the (much too long) prop shaft. I then used 4mm carbon rod axis and have not had problems since.

As from the first taxi out I noticed the airplane's tail had a mind of its own. With idle power the steerable rubber wheel worked well if not exposed to too much crosswind, but with any (taxi)power application, steering was ineffective and the tail waggled wherever it wanted. Keeping the elevator full up and using only moderate power during taxi largely eliminated that problem.

Opening the engines up for takeoff was another story, either crosswind or unequal thrust made it extremely difficult to maintain runway heading. Propwash from the engines didn't blow over the rudder, and with the tail low that rudder also didn't get any clear airflow over it untill the the aircraft reached two point (instead of 3 point attitude). It thus invariably weathervaned into the wind and if after takeoff you applied ailerons too quickly to regain runway heading, it had the tendency to tipstall and drop a wing into vertical.

After a few whisky's and long sleepless hours in bed I came to the conclusion the problem probably was caused by the 14° downthrust of the engines. During taxi and initial part of the take-off roll any power application results in much more air being blown over the horizontal stabilizer as under, creating negative pressure and thus almost cancelling any (gravity) friction of the tailwheel to steer or counteract other forces.

I thus developed a different takeoff technique, also because of the overpowered nature of this model and the desire for more scale like operation. I always taxi with stick full back and after lining up the aircraft make a dry takeoff run in my brain, forcing myself into an "unnatural" approach if things get out of hand. I mentally say 3 times RUDDER, RUDDER, RUDDER so I am well prepared to correct any deviation without aileron application because the result of the latter is often disastrous.

Now the actual takeoff. No question of opening the throttle as on many other of my planes, but VEEEERY slowly open the throttle with full back elevator allowing the airplane to accelerate down the runway with the tailwheel firmly on the ground allowing directional control. Now comes the delicate part: keeping the tail too long on the runway and the Dakota gets airborne with too low a speed for adequate lateral control. Lifting the tail too early or too abruptly and the the p-factor (gyroscopic force created by the 2 props being tilted down) and/or unequal engine power or crosswind gust, will cause your aircraft to head off one side or the other. Either you abort and try again from standstill, or open up the throttle fully to get it airborne before you get to the side of the tarmac. For the last option, keep the climb angle shallow and initially allow the airplane to choose it's direction by itself. Do not attempt to correct with ailerons until sufficient speed has built-up but use moderate rudder to just keep the wings level.

If everything runs as planned, when reaching sufficient forward speed and the plane is still accelerating down the runway, slowly release the back pressure on the stick allowing the tail to rise while applying small rudder corrections to maintain runway heading. Forget large rudder inputs because the plastic landing gear struts don't like lateral forces being applied to them. During assembly, refrain from using "hard" glues to fasten them to the wing because they will quickly show cracks and are difficult to repair. Use the "bad soft" glues you collected in other ARF's kits but didn't dare to use because you were afraid the parts would come apart (ie white FMS tubes). On the Skybus gear they are just what you need to absorb excessive forces, just check your gear after every flight, it's easy by removing the magnetic block covering your ESC's.

After the tail is in the air the airplane will accelerate even better because induced drag has been drastically reduced. At that moment, leave the throttle where it is (often barely around half throttle) and concentrate on tracking straight. If everything goes normal, the airplane will lift off by itself and climb out with a shallow angle (as the real DC3). If due to the increased and long ground roll you have trouble maintaining runway heading, at that point a slight up elevator input to clear the runway helps, but please release back to neutral immediately to allow the speed to build up.

In the air it flies nicely on ailerons, but again once on final approach, leave those ailerons neutral and pick up any wingdrop, how slight it is, with rudder. Just as before takeoff, mentally say RUDDER, RUDDER, RUDDER when you are in final approach.

This model airplane handles completely different from the real DC3 (I had a rating during the 90's) for take-off and landing, it is beautiful and rewarding but just as it's big brother requires a fine technique to operate safely.

Happy take-off and landings....
Wow! This is a lot of useful information & experience talking. I will read this post over & over to try and grasp it all and will do so just prior to going to the field to keep it fresh in the noodle I'm hoping with time that we can master these landings and takeoffs. Definitely not used to using the rudder as much. Thanks again for everyones replys.
rcflyinff is offline Find More Posts by rcflyinff
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 08, 2012, 09:24 PM
Registered User
Joined Sep 2010
38 Posts
Look at page 116 of this thread for some alternate motor choices.
Darwood is offline Find More Posts by Darwood
Reply With Quote
Old Oct 08, 2012, 11:10 PM
Chop it, cut it, bash it
quitcherbitchen's Avatar
United States, CA, La Caņada Flintridge
Joined Jul 2011
5,710 Posts
thanks looks like three options.
quitcherbitchen is offline Find More Posts by quitcherbitchen
Reply With Quote
Old Oct 10, 2012, 06:21 PM
Registered User
electricgeoff's Avatar
United Kingdom, England, Lincs
Joined Apr 2011
276 Posts
Hi from across the pond.
I originally joined this excellent forum on page 161, having bought one of these here in the UK and started a thread of my own. Then found the Top Gun one being sold here is exactly the same as the Dynam one available Stateside.
Had a number of issues with kit quality, including badly beny parts and broken Y-leads, but eventually completed the kit thanks to this forum and helpful hints and tips and the help and support of my favourite model shop, less so the distributors and manufacturers, sadly.
Got to maiden it yesterday on a beautiful clear, chilly Lincolnshire morning. See static pics attached. Couldn't resist the shots with the rainbow effects from the dewy spiders webs all across the field.
Finally settled on a C of G of 700mm (two and three quarter inches) from L/E based on all six of my Overlander 11.1V 2200Mah batteries (171grams with elastic band!) situated as shown in the last picture, with a large chunk of foam filling the remainder of the battery box.
There were no great dramatics, even though none were really expected; the first flight is always just that little bit more 'concentrating on the mind' than further forays into the blue. Five far easier flights followed with steady, 30 ft high level flight on half throttle soon trimmed in, such that I could take hands off and enjoy just 'interferring' at the end of each pass to bring her round again.
Covering some other posts I have noticed since I joined, but relating to this model:-
I did use reduced rates (75%) and a little expo (30%), but don't think I needed to. Now using 95% rudder, 90% elevator, 85% aileron, manual rudder mix to keep tail true through the turns and just 15% expo. I have only recently been persuaded to use expo, having always flown just by the 'feel' of the sticks and plane and 'gentle thumbs'. I'm still not 100% (with no expo) convinced, but using it on 6 different models now, I'm becoming comfortable with it. (and they say you can't teach an old dog new tricks!)
Our field is close mown grass and as you can see, covered in wet gossamer webs from minute spiders on the day. The castoring tailwheel was a bit off-putting initially, but with practice, plenty of up elevator at the start of the run, the gentle >5mph headwind and some tail slapping rudder use, it very quickly becomes un-important and in-consequential. Not a great problem at all really. BAF23's post was great description of take-off technique.
Although the motors didn't sound quite in sync (rcflyinff's post relates), there was no noticeable pull to one side, other than expected torque and it sounds great in the air, purring along. No tacho, so no readings available, but as my first twin, I was very pleased with results and sound that seems to resonate from the big foam fuselage.
Finally, a question.
Many of you have done some wonderful paint jobs on your models and other improvements, with lighting, parachute drops and the like.
Can anyone tell me the exact colours used on the original model (the military version sold in US markings there, in RAF markings here, that of the only VC recipient from RAF Transport Command, Flt Lt David Lord). I have tried a number of camouflage colours available over here, but none has really come close and my attempts at mixing colours has resulted in some even worse attempts.
The other thing I have done is cover the decals with a clear matt finish solution to remove the glaringly glossy ones supplied.

Thanks to all those who submit information and pictures here for the rest of us to use (and sometimes abuse) and learn from, they are all very helpful to the rest of us.

EG
electricgeoff is offline Find More Posts by electricgeoff
Reply With Quote
Old Oct 10, 2012, 07:32 PM
Flick lives
BladeHead's Avatar
beautiful, picturesque Southern New Jersey, USA
Joined Dec 2008
474 Posts
Geoff, congrats on the maiden! Welcome to the fold.
-Burt
BladeHead is offline Find More Posts by BladeHead
Reply With Quote
Old Oct 11, 2012, 10:23 AM
Registered User
rcflyinff's Avatar
United States, FL
Joined Mar 2012
563 Posts
So we received the 3 bladed props that we ordered and found that they are way to big I ordered the same size which is on the aircraft now, but this is still not right. Talking with a buddy of mine, he suspects that the previous owner cut down the 9050x3 prop to fit. This may possibly be causing the drone sound that we are hearing if the props are out of balance. I'm running twin 1400kv motors, 30A ESC's with a 2200mah 11.1v 20C battery. Anyone have any 3 blade prop suggestions for this set up? What about running a reversed prop on one? I'm also going to upgrade to a 30C battery due to the 20C was a little warm after 6 minutes of flying. Thanks for your help......Doug
rcflyinff is offline Find More Posts by rcflyinff
Reply With Quote
Old Oct 11, 2012, 11:33 AM
Registered User
United States, WI, Fond du Lac
Joined Sep 2008
1,735 Posts
GWS 8x4x3 will work and you can buy right and left hand versions. Other than a straighter takeoff roll, CR props are really not needed for this plane.

The GWS 3 blades are not the most efficient props but they do work with the stock motors.
pmullen503 is offline Find More Posts by pmullen503
Reply With Quote
Old Oct 11, 2012, 01:26 PM
EIEIEIO Classic is dway ta go!
flyinwalenda's Avatar
Northeast Pa. .Heyna or No?
Joined Aug 2009
2,071 Posts
I used the 8x4 3-blade and cut them down to 7" .Less flex and they work good.
flyinwalenda is online now Find More Posts by flyinwalenda
Reply With Quote
Old Oct 11, 2012, 04:25 PM
Montana Transplant
mt_flyer's Avatar
United States, OR, Klamath Falls
Joined Aug 2005
1,932 Posts
Quote:
Originally Posted by rcflyinff View Post
So we received the 3 bladed props that we ordered and found that they are way to big I ordered the same size which is on the aircraft now, but this is still not right. Talking with a buddy of mine, he suspects that the previous owner cut down the 9050x3 prop to fit. This may possibly be causing the drone sound that we are hearing if the props are out of balance. I'm running twin 1400kv motors, 30A ESC's with a 2200mah 11.1v 20C battery. Anyone have any 3 blade prop suggestions for this set up? What about running a reversed prop on one? I'm also going to upgrade to a 30C battery due to the 20C was a little warm after 6 minutes of flying. Thanks for your help......Doug
the "drone" sound or rollin drone is actually the rpm difference beween the two motors. if the props are out of balance you hear more of a buzz and see shaking of the prop shaft.
mt_flyer is offline Find More Posts by mt_flyer
Reply With Quote
Old Oct 11, 2012, 06:04 PM
Registered User
bettsmums's Avatar
Jacksonville, FL
Joined Jan 2006
179 Posts
3 blade props

Buy the Master Airscrew 3-blade 8x6. Tower Hobby has both tractor and pusher so you can have counter rotating props. The MAS prop blades are very stiff and will transform the plane compared to the GWS props. You have to search specifically for 8x6 3-blade MAS to find the pusher prop as it does not show up in their normal search.
bettsmums is offline Find More Posts by bettsmums
Reply With Quote
Old Oct 12, 2012, 06:30 AM
Registered User
electricgeoff's Avatar
United Kingdom, England, Lincs
Joined Apr 2011
276 Posts
Quote:
Originally Posted by rcflyinff View Post
So we received the 3 bladed props that we ordered and found that they are way to big I ordered the same size which is on the aircraft now, but this is still not right. Talking with a buddy of mine, he suspects that the previous owner cut down the 9050x3 prop to fit. This may possibly be causing the drone sound that we are hearing if the props are out of balance. I'm running twin 1400kv motors, 30A ESC's with a 2200mah 11.1v 20C battery. Anyone have any 3 blade prop suggestions for this set up? What about running a reversed prop on one? I'm also going to upgrade to a 30C battery due to the 20C was a little warm after 6 minutes of flying. Thanks for your help......Doug
Re the prop thing, I have found that the originals (8060 X 3) are very brittle (probably due to the cold wet climate over here) 'cos I snapped a blade off yesterday just catching it on the lip of the boot (trunk).

Very annoying, no wonder the kit comes with 4 props, they ain't going to last long at this rate!

Have yet to search for supplier over here, but considering looking for a shaft conversion and going for something different. Should think if I can get any 3 blade 8 X 6 blade to fit a shaft conversion, it would do.

Shame about these niggles, it's a great plane.

EG
electricgeoff is offline Find More Posts by electricgeoff
Reply With Quote
Old Oct 12, 2012, 11:34 PM
Registered User
park aviator's Avatar
Australia, NSW, McGraths Hill
Joined Mar 2008
395 Posts
hi guys i converted my dc3 over to two 8x6 mas 3 blade props by cutting the motor shafts to leave say 10mm long and using two hobbyking 3mm collet prop adaptors and now flies with much less throttle.
park aviator is online now Find More Posts by park aviator
Reply With Quote
Old Oct 13, 2012, 01:18 AM
Registered User
WVrailfan's Avatar
United States, WV, St Albans
Joined Jul 2011
1,759 Posts
Quote:
Originally Posted by park aviator View Post
hi guys i converted my dc3 over to two 8x6 mas 3 blade props by cutting the motor shafts to leave say 10mm long and using two hobbyking 3mm collet prop adaptors and now flies with much less throttle.
Can you take a couple of photos and thow them on here, I'd like to see how that conversion looks.

Thanks
Jim
WVrailfan is offline Find More Posts by WVrailfan
Reply With Quote
Old Oct 13, 2012, 06:17 AM
Registered User
bettsmums's Avatar
Jacksonville, FL
Joined Jan 2006
179 Posts
Collet Adapter for Props

I cut the shaft to 10mm long. The pusher propeller gors on the right motor.
bettsmums is offline Find More Posts by bettsmums
Reply With Quote
Old Oct 13, 2012, 08:13 AM
Registered User
WVrailfan's Avatar
United States, WV, St Albans
Joined Jul 2011
1,759 Posts
Thanks
Looks good, I may give that a try when I break a prop.

Jim
WVrailfan is offline Find More Posts by WVrailfan
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion DC-3 Plans blackwidow18 Australia 2 Jan 17, 2010 09:27 PM
Sold Celectra 4-Port 1S 3.7V 0.3A DC Li-Po Charger by E-flite dizzane Aircraft - Electric - Batteries & Chargers (FS/W) 2 Jan 15, 2010 10:02 AM
For Sale Great Planes DC-3 project sunderll Aircraft - Electric - Airplanes (FS/W) 3 Jan 12, 2010 08:34 PM
Sold Celectra 4-Port, 1-Cell, 3.7, 0.3A DC Li-Po Charger, Plus 3 240MAH Single Cell Packs. jafo216 Aircraft - Electric - Batteries & Chargers (FS/W) 9 Jan 01, 2010 12:55 PM
Sold Dynam 5-Channel Receiver/Dynam 3 in 1 Gyro CGReload Aircraft - General - Radio Equipment (FS/W) 3 Aug 18, 2008 05:40 PM