Dynam SR Trainer ARF - Page 43 - RC Groups
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Dec 31, 2012, 10:26 PM
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Thanks! i'll get a couple of the shafts and a prop ordered tomorrow. Happy New Year.
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Dec 31, 2012, 11:01 PM
Old F-4 Crewchief
fuzzyhead's Avatar
Originally Posted by MuddyWulf
Sounds like I have something else to learn in order to customize my SR. Time to stock up on paint. I have plenty of all kinds of tape. Did the maiden flight today. I felt very uneasy about the power of the 950kv motor. I snapped the screw on motor shaft on the second landing. Any idea where to get that? The prop was pretty tough though. Now I need to find a replacement shaft. I think I'm going to like this airplane once I replace the motor.
I used an Emax 2215-20 motor from Headsup RC. 200 plus watts on an APC 9x6. The added power is fantastic. Even with full flaps on a missed approach, there is loads of power to climb out and accellerate. Needless to say takeoffs are a breeze. I went with a collet type prop adapter. I'm sure I could find a spinner to fit if I looked.
Good luck.
Latest blog entry: The first F-4 I crewed.
Jan 01, 2013, 07:29 AM
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rcflyinff's Avatar
Happy New Year!!
Jan 07, 2013, 09:11 PM
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I have owned the Cirrus for around seven months now and it was the first model that I maidened.
I have flown the aircraft on the stock set up (red motor) and I was worried that the plane would fall out of the sky the whole time that I was flying. I was at full throttle for most of the flight.
Then I had a landing that ran into the slightly longer grass on the side of our strip and bent the output shaft. A replacement shaft was given to me by a fellow club member (who is an auto electrician and just happened to have a spare shaft 'out of something') and I was back in the sky in a few minutes.
I tried a different motor and prop shaft only to have that motor burn out on it's first flight and forced me into a crash landing some distance from the end of our strip. Absolutely no damage done to the airframe.
Then I tried PW-RC for spare parts for the Dynam Cirrus and found Phil to be an exellent source of spare parts including the 1100 kv blue motor and spare output shafts that, of course, fit both the red and blue motors.
The model flies much better with the slighly higher kv blue motor and is able to do basic aerobatics, where as before, with the red motor, a loop looked like a figure nine. She could just barely fall over the top even after a dive to get more airspeed. Now the machine makes nice open loops from level flight.
I do limit the wind speed that I fly the Cirrus in. In fact anything over 10 kmh sees me keep the model on the deck.
As we all know, there is not much weight to her and I just find that the model just does not handle wind. I did fly in 20 kmh wind one day and I consider myself lucky not to have destroyed the model as I was right on the limit of control. It is not fun just trying to survive.
As with a lot of others on this thread, I have also had my main landing gear pop out for no real reason except that there was no glue holding either one in place. They had just been popped into place. Well, they did hold out for several landings.
The nose gear came out on the first taxi test in my back yard, reason... no glue!
I did take the time to fit the flaps and they do work. The flaps almost bring the model to a standstill in the air.
Conclusion....The model is a very nice piece of kit let down by silly little things at the factory.
It looks and feels good in the air but I think it really needs the blue 1100 kv motor, or better, to really shine.
I fitted the flaps and they work nicely. Just remember to keep the speed up as you retract the flaps in the air or she will stall.
Speaking of the stall, very easy, the aircraft just nods it's head down a little and picks up speed but she gives very little warning of a stall.
For landing I find that you do need to keep a bit of speed on and that way the Cirrus will respond to control inputs positively. Too slow and she wants to mush a little bit.
Overall, it is a great model just with those silly issues out of the factory. Oh, and yes, mine came with bent rudder and tail fin.
Hope to fly tomorrow but the weather forecast is for 45 degrees....that is C not F!
Last edited by wrongroad; Jan 27, 2013 at 02:50 AM. Reason: spelling
Jan 08, 2013, 07:42 AM
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rcflyinff's Avatar
Hey wrongroad, nice report. Glad to here you enjoy this plane. This was my sons first plane (he's 10), he flew it a few times then decided that he wanted the flap upgrade. I did that for him. Then he wanted it painted and lights installed. I did that too. I don't suggest the lights as they are too much work for what the are. It was just a Wow! factor. Haven't flown since. He also wants to do the motor upgrade, but a friend suggested trying a larger prop. Will try that eventually. As for now, it has become a hanger queen. Oh well, might get it out soon and an give it another try. Have fun!
Jan 09, 2013, 07:35 PM
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Just a quick update, managed to get one flight in yesterday before the predicted heat wave got to us here.
I did find one more annoying problem with the nose gear.
In the factory, they make quite a tight u bend in the wire just as it comes out of the base block in the fuselage. It causes the wire to fracture and, as happened to me yesterday, fail on landing. I will admit to hitting a dried cow pat but the resulting nose over was hardish.
There was no damage to the airframe or the propeller or output shaft. That is because I have spares......you all know the drill here I am sure...if you have spares, you never need them !!!!
Just keep an eye on that bend. I am making a new on today and I will be not putting in the u bend. I know it is there as a spring but I think the chance of failure due to a fracture out weighs the very, very slight spring effect.
@ rcflyinff, are you not flying because of winter time or just have other things on the boil?
One thing about our neck of the woods, we have fairly good weather all year round to fly in.
Yesterday was a bit of a one off but we do get that type of day every so often. Usually when there are bad bush fires (forrest fires) around and we have that happening right now. Not close to where I am but close enough to feel for my country men.
Regards and respect to all
Jan 10, 2013, 07:56 AM
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rcflyinff's Avatar
Hey wrongroad, the SR has been hanging around due to all of the upgrades, painting, lights, ESC (for the lights) and other plane projects. Took it out to the field a few weeks ago but was not happy with the range check, so I decided to put it back in the truck to fly another day. Haven't messed with it since as we got three planes under the Christmas tree that are keeping me busy (AT-6, TurboJet & Grand Cruiser) I too have had problems with the nose gear. Mine mainly being very loose & sloppy. The nose gear and the belly battery compartment are the main flaws of this airplane. Hope you get some good flights in and watch out for those cow patties
Jan 17, 2013, 04:18 AM
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G'day gang,
Just to update things on the nose gear landing strut... once I had the broken parts out I quickly realised that the u bend is there to slip into the notch in the nose gear steering control horn.
So I made the u bend on a much larger radius than the original strut and then filled the inside part of the u with epoxy.
This makes for a larger 'key' section something akin to a woodruff key. Much more surface area for the u bend to fill the notch and therefore easing the loading on the plastic control horn.
I used 2.4mm stainless steel rod to make the new nose gear but it did take three goes to get it right.
It was a very cheap fix (the shop gave me the rod for free once I showed him what I needed it for, he was very impressed with the model). The hardest part was bending the rod with pliers and hand strength.
Back to the runway yesterday and the Cirrus flew without fault and, to test my workmanship of course, I gave her a heavy landing....just to check her out. (lol) All was good, all was well except I forgot to take the battery hatch with me (I am Stupid some times, so much for my check list) and I was not ready to risk a battery falling out even though I have fitted extra velcroe straps over the battery mounting void.
Still, she flew well and handled nicely on the ground with out having to trim anything at the field.
Good flying.
Regards and respect
Feb 03, 2013, 10:36 PM
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rcflyinff's Avatar
Well we finally got her back in the air today. Flew nice, but what a slug compared to the new planes we are flying My son was being coached by a friend while landing with flaps when he stalled it and had a rough landing. First motor shaft snapped Oh well, I expected this to happen after reading everyones posts, thats why I ordered spare shafts when we ordered the plane. My buddy suggested upsizing the stock 9x5(or 6)x3 to a 10x6x3. Anyone have the 950KV motor and installed the bigger prop. I happened to have one and installed it with a collet adapter. Need to do an amp check yet. On another note, the club we are joining has a well manicured grass strip, but I'm still very leary of the nose gear. I have had nothing but trouble with this gear even on asphault. Anyone done any upgrades or replaced it with something stronger. Also, I suspect I'll have to remove the wheelpants and install bigger wheels/tires to help her roll through the grass. Any suggestions? Thanks in advance for your help.
Feb 03, 2013, 10:39 PM
Always puts it on the numbers.
Spookeay's Avatar
I put 1100KV motors in mine. At the cost of $15 it's worth it. I don't for the life of me know why they don't put them in stock, the 950's are a stall waiting to happen.
Feb 04, 2013, 10:35 AM
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rcflyinff's Avatar
Originally Posted by Spookeay
I put 1100KV motors in mine. At the cost of $15 it's worth it. I don't for the life of me know why they don't put them in stock, the 950's are a stall waiting to happen.
I believe I will take the advise of experienced pilots such as yourself and upgrade to an 1100kv. I was looking at the PowerUp Sport 450 on headsuprc.com, but they are out of stock They have the Emax BL2215/20 Outrunner Brushless Motor in stock but it is 1200kv for $20. Is this a little overkill or should I just wait till the 1100kv comes available? No huge rush as we have other planes to fly. Thank you.
Feb 07, 2013, 09:56 PM
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rcflyinff's Avatar
Originally Posted by Apprentice15e
Thanks guys...

I flew this configuration today, and boy it flies really sweet!! It is really zippy... it is like a new plane!!!

Two things I should mention:
1. For the Apprentice nose gear, you will either you will have to use an arm from the Apprentice's firewall or have to devise something else. The original arm might work but you will have to create some kind of bend in the nose gear similar to stock nose gear wire. The Apprentice's firewall is not that expsensive, I think 7 bucks or so.. I used the arm from many of the broken ones.

2. I used epoxy to glue the landing gear plastic inserts (that are attached to foam in the stock set up) to give strength to the landing gears.
Thank you for the upgrade info. Where can I purchase the Apprentice firewall? Also, I'm waiting for headsup to get the PowerUp 450 Sport motor back in stock. Are you runnning the stock 9x6x3 prop? What battery are you running?
Feb 14, 2013, 01:04 AM
Registered User
G'day gang,
@ rcflyinff, mate, I was just thinking about a better way to do the nose gear strut on the Cirrus and after making a new one for mine I have thought it out a bit better and this is what I think I will do for another strut.
I will make another strut but leave the u bend out and fit a 2.4mm collar to the strut. This collar would be shaped to a vee on one side to act as the steering guide. A few minutes on the grinding wheel will soon make the vee section. Just keep your fingers clear and have a tub of water handy to keep the collar cool.
Once in position you only have to tighten the grub screw to keep it in place.
If it helps you out at all, I am using a 11.1volt 25c 2300mAh battery in my Cirrus and it does not effect the CG in a bad way, in fact, it gives just a fraction more nose down. Just a fraction. This is with the 1100kv motor with the stock prop and I can get a good ten minutes at about 75% throttle. This gives me time for the odd go around if needed.
Hope this is of a small help to you.
Regards and respect
Feb 14, 2013, 02:31 PM
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rcflyinff's Avatar
Thank you for sharing your ideas wrongroad. Any chance you could post some pics of this mod. Ordered the PowerUp 450 sport motor today. Hoping this will bring her to life Also ordered some bigger wheels/tires as we are joining a club with a grass runway only.
Feb 14, 2013, 04:09 PM
Registered User
Here is a motor that would be perfect for this plane

http://www.hobbypartz.com/96m601-big...20-1100kv.html. I have several of these motors in various planes and they perform very well. They are quiet and runs very smooth

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