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Aug 06, 2019, 05:13 PM
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Question

Slow Biplane Wanted


I'm looking for the slowest flying foam electric pnp/bnf biplane I can get. In other words, the lowest wing loading of available choices. The following are under consideration:
- Eflite PT-17 1.1m
- Rochobby Waco
- Dynam Tiger Moth
- Dynam Waco

After building two Dynam kits I swore I'd never build another (quality control issues you wouldn't believe), but they are among the few Biplane choices available.

Unfortunately mfg's don't provide wing area and flying weight specs like they used to, so calculating WL/WCL is not easy. 50 years of RC flying have taught me that WL/WCL are good indicators of flying speed.

Question #1: Have I overlooked any choices?

Question #2: Does anyone have any experience to share regarding the flying speed and or WL/WCL of these planes?

After building many biplanes in the past, I decided I would never build another due to their inherent hassles. I originally started looking for a PNP/BNF foamie of about 50-60" with the lightest wing loading (e.g. the slowest). I'm looking for slow and relaxing flying, with basic aerobatic capabilities. My current favorite plane is an Eflite Conscendo I hopped up (before the Conscendo Advanced came out). I have a plethora of other powered gliders. My 50 years of RC flying are coming to an end, and after building over 100 planes I'm no longer interested in doing that. And I can no longer do the "pattern" aerobatics I used to be involved in, but enjoy doing "slow motion". basic+ aerobatics (e.g. loop with roll at top). Hence my search for a "geezers" plane that looks cool! (Golden Age?) )

p.s. Yes, I had a Slow Bipe at one time. Fun but squirrely.
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Aug 06, 2019, 06:15 PM
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I may have just answered my own question. Maybe the E-flite Timber X is what I'm look for. Slow and aerobatic?
Aug 06, 2019, 09:08 PM
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JohnM's Avatar
Quote:
Originally Posted by royp
I may have just answered my own question. Maybe the E-flite Timber X is what I'm look for. Slow and aerobatic?
The E-flite Timber X isn't a bi-plane but it can be flown slow and for a high wing plane it is very aerobatic due to the very large control surfaces. A lower wing loading could probably be found in a aerobatic bi-plane such as the Mamba 10 or similar. The UMX Pitts is also a good candidate for all 3 of your requirements.
Aug 07, 2019, 01:23 PM
An itch?. Scratch build.
eflightray's Avatar
If non-scale models are acceptable, what about the 3D biplanes, there are quite a few.

They are certainly capable of slow flight and aerobatics, just dial down the control throws to make them less sensitive.

.
Aug 07, 2019, 02:26 PM
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Thanks for your responses. Much appreciated.

I finally came to my senses on the Timber-X in that (1) I already have a plane that flies like the Timber-X -- a QQ Extra 300, and (2) the WCL on the Timber-X is 8, but the WCL on the PT-17 1.1m is only 5 (i.e. it's slower in straight and level flight).
Aug 07, 2019, 07:48 PM
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I've had my Dynam Tigermoth for 4 years now, it's a great plane and one I'll replace if ever destroyed. The only changes I made were to use larger hardware on all the wing/cabane mounts, raking the gear forward, and replacing the wheels with 3" Dubros. It's a great plane for putting around and has an awesome presence, check the long running love fest thread in the warbirds section.

The Dynam Waco is also on my list, seems it can be flown slowly but has some speed and aerobatic ability as well. The Tiger Moth can do nice loops but if you want to do rolls consider the Waco or even the Stearman, which I'd also like to have!
Aug 08, 2019, 12:46 AM
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Quote:
Originally Posted by Citationfxr
I've had my Dynam Tigermoth for 4 years now, it's a great plane and one I'll replace if ever destroyed.
Thanks for the info. I'm considering the Tiger Moth, but replacing the motor with one that will run on 3 cells, in order to make it lighter. I did find some wing loading information, and it supposedly has a wing loading of 19 oz/sf. That can't possibly be right can it? The E-flite PT-17 1.1m has a WL of 11 oz/sf (WCL of 5). If the Dynam TM actually does have a wing loading of 19, then that would indicate it has a high stall speed (not the slow flyer I'm looking for). Interesting you moved the wheels forward. That's what I thought would have to be done just from looking at the pictures. That's a plastic gear strut isn't it? Did you make a new one out of wire? That's what I did on a previous Saito 25 powered TM I had.

Can you provide a link to the Tiger Moth thread you mentioned?

Thanks.
Aug 10, 2019, 06:45 AM
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Quote:
Originally Posted by royp
Thanks for the info. I'm considering the Tiger Moth, but replacing the motor with one that will run on 3 cells, in order to make it lighter. I did find some wing loading information, and it supposedly has a wing loading of 19 oz/sf. That can't possibly be right can it? The E-flite PT-17 1.1m has a WL of 11 oz/sf (WCL of 5). If the Dynam TM actually does have a wing loading of 19, then that would indicate it has a high stall speed (not the slow flyer I'm looking for). Interesting you moved the wheels forward. That's what I thought would have to be done just from looking at the pictures. That's a plastic gear strut isn't it? Did you make a new one out of wire? That's what I did on a previous Saito 25 powered TM I had.

Can you provide a link to the Tiger Moth thread you mentioned?

Thanks.
The landing gear is heavy wire, plastic parts are just decoration, you will need to shorten the metal strut on either side but that's easily done.

I'm a dummy copying links with this phone but the Tiger Moth thread is currently on the first page of the electric warbirds section. I don't have wing loading numbers but what you're stating seems high. I'm no expert pilot but the TM is one plane I've never stalled, unless it's been practicing at altitude. It's also not great for aerobatics, I think the Eflite Stearman could let you put around, do some aerobatics, and keep batteries to 3S if that's what you're after. They're all good choices, good luck!
Aug 10, 2019, 07:35 AM
Flying a Falcon or a 3D model.
fauconnier's Avatar
Sorry, it's not a foamie.

Precision aerobatic planes are very light. They have a 60" biplane. With a lighter sport set-up instead of a 3D set up the wing loading will be super low.
Last edited by fauconnier; Aug 10, 2019 at 07:42 AM. Reason: It's not a foamie
Aug 16, 2019, 10:19 PM
Registered User
You may want to look into the Twisted Hobbies 35" Crack Fokker. I have one, it is super slow, very aerobatic, good for indoors or out. One of my favorite planes. https://twistedhobbys.com/th-35-epp-...ri-red-yellow/
Aug 16, 2019, 11:59 PM
If it flies, I can crash it.
rocketsled666's Avatar
The Dynam Waco will fly very slowly. Even overloaded with a 4400mAh battery and a MrRC sound system with two transducers, mine flies slower than scale. But it will fly for 7 minutes or so on a pack half this size (and weight) and in that configuration it's about as slow as you could hope for without going to something specifically designed to fly slow. But when you crack the throttle open it will really scoot and it becomes quite aerobatic.
Aug 17, 2019, 02:31 PM
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Quote:
Originally Posted by raypri
You may want to look into the Twisted Hobbies 35" Crack Fokker.
Pretty much the air speed I was looking for. Thanks for the excellent tip. I would order this today except that I have decided not to do any more "builds", and this looks per the manual to be a pretty intensive one. Love the plane though! In fact I'm drooling!
Aug 17, 2019, 02:40 PM
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Thread OP
Quote:
Originally Posted by rocketsled666
The Dynam Waco will fly very slowly.
Thanks for the feedback. I'm leaning toward this or the Tiger Moth. Even though I could write a book about all the problems I've had with Dynam models. The wing loading Dynam gives for the Waco can't possibly be right. Would you mind weighing your Waco empty (no battery) and letting me know what it is? Also could you please measure the length and width of both wings so I can get a wing area? Would much appreciate this info. THANKS!

p.s. The reason I would go for the Tiger Moth is that it has a longer nose, so that if I use a lighter battery (1800?) it would be easier to add weight way forward to compensate for CG. Alternately I could use a prop weight which I often do on short nose planes, which is as far forward as you can get!
Aug 17, 2019, 11:31 PM
If it flies, I can crash it.
rocketsled666's Avatar
Sure, I can weigh it. But I'm carrying extra ballast with the Mr.RC sound system so it's not going to be exact. I cannot easily remove it, but probably you can look up the weight on line... I'll do that tomorrow.

Trust me, though, it's a featherweight. I have the e-Flite PT-17e (the original stick and film model, not the foamy they sell now. It's got a smaller span than the Waco, but I fly it with essentially the same power system, including the 4400mAh 4S battery. The Stearman needs to fly a bit faster than the similarly loaded Waco but it's still not all that fast, meaning the Waco really is a slow flyer.

The e-Flite PT-17e nose *is* short. The pack sits almost directly under the CG. The only adjustment you can make with the pack is to make the plane more tail heavy. To balance the plane, it needs nose weight. I used a larger motor (Horizon recommended Power 15, but I used a Power 32 instead) and still added a 2Oz "Higley" prop nut and maybe another 2Oz of deadweight to get it to balance. In comparison, the Waco balances with every pack I've tried. Plenty of room to move.
Aug 18, 2019, 02:04 PM
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Thread OP
Thanks for the info. Attached is my PT-17e built several years back. Much lead under the motor to get balanced. I let a friend fly it, who spun it in for a major repair job, so is even heavier now. I don't fly this anymore as the wing loading makes it no longer fun for a 76 year old!

Have you tried flying your Dynam Waco with a 3S battery? Just thinking of things I can do to minimize wing loading.

Looking forward to your measurements.


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