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Feb 04, 2017, 02:27 PM
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Question

DB autogyro


Was thinking of building the DB sport twin autogyro which is supplied in kit form but also thought about building the DB Gyrace from a plan and was wondering which of the two was the better regarding twin autogyro.
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Feb 04, 2017, 04:14 PM
can you land on that ?
Without a doubt the DB kit is the easiest. The current version is a simplified box fuselage and thus lighter than the scale-ish one which I think is from a plan. The Gyrace is a bigger version and needs quite a few mods to be an effective flier according to some experts. All three being twin-rotor are an easy route into rotating wing flight. I didn't succeed in making a wingless version fly, seems they need the stub wings for that little extra lift. The www.autogyro.com site had a list pf mods for the Gyrace, has anyone got a link ? I`ll dig out some old pics of my attempts.
Feb 04, 2017, 04:28 PM
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Thank you for your advice, most likely go with the kit version then. I did build and fly a Tom wright single rotor Crane fly and regretfully sold it. I also have built the EPP Whippit and is still waiting to be finished.
Feb 05, 2017, 07:30 AM
Registered User

DB gyro


Hi Glenbees.

The scale-ish DB gyro was a kit from years ago, I built one and it was a very good flyer,
unfortunately I have not got the plan.

Dave.
Feb 05, 2017, 07:40 AM
can you land on that ?
Yes it is a good flier Dave. I must have a rummage through my plans, forgot it was a kit. The "wingless" one was named Shakin` Sheila because of vibrations in the wire struts, an upside-down undercart ! BTW that link is not the model one that used to exist, Has the excellent R/C gyro been archived somewhere ? I have Gyrace plan itching to get dirtied.
Last edited by arrow5; Feb 05, 2017 at 07:54 AM.
Feb 05, 2017, 09:53 AM
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Thread OP
There is actually a Gyrace for sale on ebay at the moment but what put me off was some kind of box at the front end covering the motor, don't know why.
Feb 05, 2017, 12:31 PM
can you land on that ?
Yes I looked at the ad, pity about the box type motor mount, a vintage cowl would be more in keeping with the vintage style. Fair price for all the bits.
Dec 11, 2019, 11:48 AM
Thermals, Tom
RyanNX211's Avatar
The DB Autogyro has tapered blades. Which side is the leading edge?
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Dec 11, 2019, 04:39 PM
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PaulB's Avatar
Mine didn't (around 1994).


Paul
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Dec 25, 2020, 06:36 PM
Falcoholic

Early DB gyro


Here’s my copy, built off a very early set of DB plans. (Pre-rebuild)
Note it had no fins at the stab tips and the blades were glued together.
I flew it several times. It threw a blade from memory (no real problem) and was quite directionally unstable. I recall the plans showed the area between the wire on the legs filled in with balsa. Mine was a copy of a friends gyro. He reported it as even worse directionally with the legs filled in. I believe that was the original reason for the extra fins, to improve it when the legs were filled in.

I’ve recently resurrected it for a rebuild. Half the fuselage needed rebuild, the complete tail and at least one rotor. I’ve put the extra fins on this time and improved the build method to hopefully avoid the external triangle gussets, which seem to bug me these days. I love the look of the “scale” one so I might build a new fuselage at some point.
Last edited by Falcogeorge; Dec 26, 2020 at 03:26 AM.
Jan 03, 2021, 12:10 AM
Falcoholic
Rebuild complete ... new back half fuselage. New complete tail. New nose. Electrification from its old OS25.
Balance was an issue. To get the CG right, there really wasnít an easy way without adding lead or having to remove the wing to replace batteries. I prefer lead. 1.2KG without battery. Some of that is lead in the nose. I put the battery compartment just behind the wing and printed a battery box and a vented hatch. The cooling inlet is under the nose aíla NACA vent but with no internal ramp.
The spinner was printed from someone elseís design with a small change to the backplate to have nuts from behind rather than screwing into posts that have a tendency to snap off.
Fingers crossed for maiden tomorrow. Iíll try to remember to film it.
Last edited by Falcogeorge; Jan 03, 2021 at 12:15 AM.
Jan 03, 2021, 09:30 PM
Falcoholic
DB Autogyro Maiden Flight (5 min 20 sec)


I suspected it was to be underpowered. The motor I used was just one I had lying around. It sure showed it! It managed a very poor climb at the start then level flight was about the best it could do. I will try a 4S pack next, which should be an improvement.
I also had one rotor spinning faster than the other which affected the trim somewhat. On later inspection, the wing, which I hadn't rebuilt, had rotor posts that weren't parallel. This meant that the one with lower incidence spun slower. I'll fix that for next time.
So all in all I guess it was successful. It should be a lot more fun to fly once I get the bugs fixed.
Jan 03, 2021, 11:16 PM
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britinoz's Avatar
I thought that looked like quite a respectable maiden flight. I'm sure you realize that autogiros tend to fly a little slower than fixed wing models...so In my eyes your model was scooting around reasonable fast.
Re the power. This kind of model usually runs between 6 and 10 deg down thrust on the motor.
Happy Landings
Chris...
Jan 03, 2021, 11:40 PM
Falcoholic
Yes.. it was a fine balance between level flight and decent. Full power could just hold it level with the right pitch input. Any more or any less and it descended.
It has all the original down thrust etc. the thrust as is, is way less than the original 25 it had. The motor isnít really the right one but itís all I had in the drawer. Iím sure a 4S kick should do the trick.. I just need to fix the pylons and it should be good to go again.
Jan 07, 2021, 11:45 AM
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Tick Point's Avatar
I'm puzzled why the blades on these lack an airfoil. They look like paint sticks, but they fly! If I scratch built some blades with an airfoil, perhaps small deviations result in poor performance. Paint sticks would be nearly identical.
Dave


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