dphill2

My Feedback: (1)

Tony, how well does those Elect Retracts work ?? And have you had any problems with them ?

Dave

Super08

My Feedback: (2)

I wouldn't mind some more details on them as well. I was looking at the HK site but was unsure as to which ones you had. They have quite the assortment.

Tony Iannucelli

My Feedback: (193)

Hi guys. I use those retract mechanisms in several planes and one helicopter. They have never failed me. That being said, it doesn't mean they can't fail. I'm saying they have been trouble free -perfect- for me, and at the price, I don't think they can be beaten. I've had more than 100 flights, maybe even 200 on them in different airframes, including an H9 Spitfire, a Kyosho Focke Wulf, a TF AT-6, the Birdy, and a Century A109 helicopter. I wrote some stories about the Spit, the Birdy, and the helicopter on modelairplanenews.com. Search "Tony Iannucelli" and they will pop up. The articles give a lot of detail. The gear does not come with struts but they use a 5mm strut, and Top Flite's Mustang 60, the TF P-47, and the AT-6 are all 5mm and are very strong steel. I'm sure other ARFs out there also have 5mm wire. The AT-6 gear are bent funny, but with these they really work well. I made some plywood plates that fit over the frame of the gear to add strength. Not necessary, but in the case of the heavy AT-6, I didn't want to take a chance of whacking them. Here's the link -- http://www.hobbyking.com/hobbyking/s...m_1pc_54g.html

By the way, the nose gear in the Dirty Birdy is mechanical. I happened to have one, and it didn't require any extra effort. It made more sense to have a hybrid system and the article explains how I did it.

dphill2

My Feedback: (1)

I was hoping you would tell me you had 100 flights on a 3 gear set from HK. I guess by what you did, they don't have a Tri gear set ??
back in the 70s I flew kraft elect retracts and enjoyed the reliability of them and the Ease of installation. They were some what heavy, but worked so well it was worth the extra weight. I sure wished someone would come out with a good 3 gear set of Reliable elect retracts !!!!

Dave

Super08

My Feedback: (2)

This looks like the matching nose gear but it mounts differently, not sure if it would work. Cheap enough to buy one and see I suppose.
http://www.hobbyking.com/hobbyking/s...1mm_Mount.html

Also the mains can be bought as a set. These look to be the same but in a pair, you would save about 3 bucks over buying the mains by themselves.

http://www.hobbyking.com/hobbyking/s...unt_2pcs_.html

Tony Iannucelli

My Feedback: (193)

Actually, I tried many of the electrics. The problem with the one Super08 is showing is that the mounting pattern doesn't fit. The plane has to have the gear drop from the mounting side down. The motor and mechs have to be on the opposite side of the one shown in order to work. There are none like that, and believe me, I've tried a lot of them. If the fuselage wasn't fiberglass you could build a mount, but to make all three electric -- with the work involved -- wasn't worth it to me. And I already had the nose gear which dropped right in.

I had some used Multicons. The new ones are FAR superior in my opinion, and do not require the box inside the airplane. And they were 5/32s, not very strong. Just my opinion of course. Ask my wife, my opinion is not worth a lot.....

Super08

My Feedback: (2)

That is what I suspected with that front mount. A person would have to use spacer blocks on it and then I wouldn't trust it to hold.

keithtsr

My Feedback: (3)

On my second DB I used an old set of air retracts. I had to make blocks for them. It was pretty easy to do. I made the blocks, sanded down the inside of the fuselage and used milled glass and epoxy them im. After the epoxy was cured I drilled two holes in each one and used 3/16" wooden dowels that run down into the factory mounts with a little epoxy. Solid as a rock and only took about 30 minutes to do.


So it's possible to use them it's just going to take a little work.

Super08

My Feedback: (2)

I started toying with the idea of using the 75AX I have here NIB now that I know the guys are using NovaRossi engines without issue which are over 600g. The 75AX weighs less than the NR does at 578g. The Nova's are in the 600 range. The 75 has the same stroke as the 65 and the same mounting footprint, just a larger bore. Makes me wonder how it would run on a pipe with about a 12x8~9 prop. I am sure an 11x8 would be too small. The other thing is I don't know what the ground clearance is like with a 12" prop as my plane is still en-route to me. The other option would be to go with just a Macs peace pipe muffler.

Tony Iannucelli

My Feedback: (193)

I went as far as fitting the blocks...but it looked like a mouse job to me, and the Hobbico nose gear was a prefect fit. I used the servo speed adjustment on my transmitter and all three gear go up and down together. Nice!

Super08

My Feedback: (2)

I found a guy that ran a pipe on his and was shy of 13k with a APC 12x8 but had not cut the header down to tune it to the prop. I bet a person could break 13k with it or drop down to a 12x7 or 11x9. It could be an interesting experiment. I don't have to worry about the engine size as I don't compete.

Tony Iannucelli

My Feedback: (193)

The retracts I used can not be bought as a set. The ones Super08 points out have a metal stub and are designed for Robart type struts, not wire struts like the Birdy uses. They are nice, and the metal trunnions are great if you use struts that will work with them. The ones I used have twin grub screws holding the wires, one on each side. I use TWO grub screws on EACH side so no loctite is needed. The brass is soft and loctite makes them difficult to remove, even the blue stuff. There definitely are a lot of options to set up the gear on this plane.

jgracco

..

CRX Turbines

I built the dirty birdy as a kit off this site. If your interested in kits save yourself 150 and build it yourself.
This is one of the fastest planes I own. The build is clean and it works well....

http://bridiairplanes.com/hangar/dirtybirdy60.html

Oh BTW this is as close to the original Joe Bridi models as you can get....

Andy

JimDFlyer

David,
I sent you a PM on RCG DB thread the other day. My question was re engine selection for the DB 60 ARF. I have an OS 55 AX NIB, an OS SF 61 NIB, an OS 61 SF-P new, and an OS 75 AX NIB. I just went through my engine stash and found the two OS 61 SF's. I like the idea of the much lighter 55, think the 75 would be too heavy. The 61's seem like the Goldilock's choice. The pump would allow mounting larger fuel tank back from the firewall. Does that seem like the best choice?
Jim

doxilia

My Feedback: (3)

Jim,

got your message just haven't had a chance to reply yet. I agree with your assessments on engine choice. I think a 55AX would do well provided your model is light - ideally no more than 7.5 lbs wet. I don't have an ARF so I don't know how they turn out but I'm aiming for a sub 8 lb glass/foam fully painted version with a Rossi 60 (i.e., heavy engine). The 75 is too much weight, power and fuel IMO. The 61SF's are nice but they are long strokes better suited to 12x8 / 12x10 props. I feel the DB is a "short stroke" design for 11" props but that doesn't mean the SF wouldn't fly it. The pump certainly allows you to move your tank back and your steering and throttle servos forward.

I'd (rather, I will) use good mini servos at ~1 oz weight and over 50 oz in of torque on controls and 2 lighter 0.7 oz minis on steering throttle.

I hope this helps,

David

Tony Iannucelli

My Feedback: (193)

Don't know if it helps, but I'm running a 61SF non-pumped in my Dirty Birdy with a Macs muffler. It's four ounces lighter than the OS muffler and it works very well. You can hear the engine "come on the pipe", even though it's a muffler, not a pipe. I run a 61SF Pump on a Suprafly 60. I really can't tell the difference in performance, both are fast and smooth, but the Birdy is a bit faster. The Suprafly land a bit more slowly. Tank position on the Dirty Birdy seems to be perfect for the non-pumped engine. I run an 11-10 propeller on it, and it's perfectly matched to it. The engine is long-stroke and the prop makes it quiet and fast. The only downside of the higher pitch is a quicker landing. Verticals are ballastic and go forever. Not sure, but I think the 75 is lighter than the 61 and is a good option too, but finding the right prop and dealing with ground clearance might be an issue. --Tony

doxilia

My Feedback: (3)

The 75 is about 1.5 oz heavier than a 61 SF at 19 oz. Power of the 75 at ~2.3 bhp almost at par with the NovaRossi Speed/13 (a RE engine) albeit at higher fuel consumption (probably). On the other hand, the SF is heavier and more powerful (~1.8 bhp) than either the 55 or 65 AX which have similar power outputs at ~1.7 bhp.

David

JimDFlyer

Thanks for your response. I found this current thread on RCU and noted your contributuions. I was originally considering the 75 but agree that it suffers from weight, fuel consumption and requires a greater diameter prop. I have one on a Four Star, it's a moose of an engine but sweet running. I was thinking of the 55 due to weight and similar bhp to the 65 AX. Recommended prop on 55 is a 12X7 or 8. I know the 55 to be a smooth, powerful engine that is fairly easy on fuel. I will have to do some cogitating on how to lighten the DB. I plan on electric retracts and could certainly use light weight mini servos for R/E/A, micro for throttle. 8 oz fuel tank might be practical with the 55. Any thoughts on further lightening? I have a Macs quiet header for both engines, a Jett muffler for the 61 or 75.
Jim.

doxilia

My Feedback: (3)

Jim,

it might be worth while checking out the weight of the airframe components parts. If the airframe is under 4 lbs, I think you stand a chance of bringing the model in at 7.5 lbs wet. Make that 7 lbs dry if you remove the 8 oz of fuel. The 55 is a 14.5 oz engine so if you add another 4 oz for the exhaust (header and pipe), 8 oz for retracts, 8 oz for radio you'd be looking at a model around 6.5 lbs without hardware or other odds and ends. It sounds doable.

For what its worth, there are a few Japanese designs such as the Dash 5 45 which have the same physical dimensions as the DB60 and specs of 6.2-7.2 lbs all up. These models are designed for piped 45-49 RE engines. Those designs could be built to the lighter side of the specs with a little re-design of the airframe and modern light radio gear.

David

PS From the photos below you'll see that others have thought of using the 55 before. Those are from Tim's build (fuse made from a mold made from an original BHE glass fuse plug). The plan was to use the 55 but he eventually changed his mind to use a NovaRossi 60 SE. He never flew it with the 55 so there were no comments on the combo.

CRX Turbines

I built mine and powered it with a 90 Super tigre... I thought it might be overkill but figrued I could always put a smaller engine on it if needed but I never got there. This thing flies smoother than anything I own and drills holes in the sky. it is the perfect plane to go fast with or to lay back and fly on a sunday afternoon....

Andy

JimDFlyer

I have a gaggle of planes, some I never fly, some I fly often. My favorite plane to fly recently has been an Extreme Flight Vanquish. It always gets compliments on how well it flies, despite my limited skills. I bought the Dirty Dirdy to have a larger, glow-powered plane with similar smooth characteristics. The choice of powerplant will impact much of the rest of the assembly of the DB. I have read about addition of ounces of lead to the tail and concerns about flight times with the stock fuel tank. I don't expect the DB to fly 3D and already have several hot rod fast planes. My goal is smooth and graceful aerobatic plane.

Tony Iannucelli

My Feedback: (193)

Jim, don't add lead. It's not necessary. Mine was a bit nose heavy, but the solution with the OS 61 engine was to lose the muffler in favor of a Macs black muffler. I think the Macs was four ounces lighter than the OS, and that made the difference. It balances neutral and flies superbly. Only my piloting skills hold this plane back. My Birdy came in at 8 pounds one ounce with a Kraft 16 ounce slimline tank and a five cell battery mounted behind the servos.

CRX Turbines

I was peasently surprised with this plane. Very.. you can go fast or slow... it flies like it is on a rail and goes extactly where you point it but it is light and hauls when you want it to haul. It is just very comfortable at any speed. It also handles any winds you throw at it. Not a floater and not a lead sled... I call it my butter plane because it just flows like melted butter...

Andy

doxilia

My Feedback: (3)

I think Tony's setup reveals the possibilities. A few folks fly wood DB's (highly modified) in SPA with 55's delivering ~1300W. The 61 SF delivers closer to 1400 so the power difference is not huge - about 100W.

The thing I find interesting, particularly with a "small" 60 size classic like the DB (less than 700 squares) is the weight difference between the two power setups. Assuming a Hayes 16 oz tank with a 61 to 90 size engine, we're looking at 18.5 oz of juice (tank included) plus the weight of the engine which varies between 19 and 21 oz. Averaging, it stands at 38.5 oz (exhaust not included). With a 50-56 size engine (NR make a 57) one could go as low as 9.5 oz of juice (tank included) and 14.5 oz for the engine for a total of 24 oz, again, without exhaust. That's about the maximum weight difference as 8 oz of fuel is the lower practical side for models this size.

This also assumes no tail weight with the heavier setups but all in all ones looking at 14.5 oz differential which translates into a model weight of close to 8 lbs wet with 50-57's and 9+ lbs wet with 61+ engines. Given the 690 squares of wing, the former approach strikes me as a viable pattern setup for this ARF.

David