# Thoughts on a new biplane design?

Discussion in 'Hangar Flying' started by cluttonfred, Sep 3, 2018.

1. Sep 7, 2018

### Monty

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Biplanes....

Well.....frankly, a cursory search of barnstormers leaves me with the feeling that unless you just have a burning desire to build one, there is no real reason. You can buy one already assembled and flying for less than the cost of the engine. Fewer and fewer people are interested. I don't expect mine will retain it's value, or that I will sell it for more than I bought it, even though I have put quite a bit into it. I don't really see the need for a new design, unless that is just your particular thing.

They are fun-I have one. But a biplane is not a refined, perfected aircraft. They are great for learning to land a blind tail wheel, uncoordinated use of the the rudder, and coordinated-uncoordinated use of the rudder, plus aerobatics. The aerobatics part, mostly because it would be difficult to exceed 160 mph in a vertical dive with full power, and they are structurally robust (mine anyway). They are not a good cross country machine, and the mono-plane long surpassed them in all aspects. The power off descent is eye watering....Still, there is something there.... People look at you differently when you land and taxi up in a single seat open cockpit biplane. Sometimes a bit sideways.... They have quirks, smells, and habits that you only get from flying one. I was asked, how do you get checked out in that?.....Strap one on, that's how! You won't regret it.

I'm glad people have time to build them.

2. Sep 7, 2018

### Victor Bravo

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Fritz you busted me again ! I was always intrigued by the TP biplane. The red on in the middle fired off a whole lot of my neurons, mixed with great memories from model airplane days. Slightly modified outlines of that airplane (the one with the upper swept wing) would make a full-scale version of one of the greatest models ever designed, the Andrews Aeromaster.

3. Sep 7, 2018

### FritzW

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During a rebuild the red one apparently went from this:

...to this: It wouldn't take much to make a fullscale Andrews Aeromaster out of a TP Chuckbird.

As far as childhood model biplane memories: mine would be the Wagner Dakota.

maybe not as sexy as the Aeromaster but it's so cute you can run the engine on kitten farts.

4. Mar 6, 2019

### cluttonfred

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5. Mar 7, 2019

### Himat

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Design something that look modern:

6. Mar 7, 2019

### cluttonfred

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Bof, if I wanted modern why go with a biplane? I’d much rather have something like that Colobri. Different strokes..... ;-)

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7. Mar 7, 2019

### GeeZee

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Well, I haven’t seen mention of Mr. Ed Fishers Lil’ Bitts biplane. It’s an standoff scale Pitts replica (LSA). The plans are being sold by our very own addictedtoclimbing. Oh yea I just bought a set and have been studying them. I still have lots to figure out but it looks reasonably simple. Traditional steel tube fuse and aluminum tube spars. For power I’m thinking Pegasus O-100 or Verner radial. Really leaning towards the radial.....

8. Mar 8, 2019

### ScaleBirdsScott

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I like the look of a Pitts with a radial, and a Bitts with a 5-cylinder radial has passed my mind oh, a few times, since seeing it.

I'm looking forward to pre-welded frames for the Bitts to come down the pipe.

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9. Mar 8, 2019

### GeeZee

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I would consider one of those pre cut tube kits that addictedtoclimbing has talked about if it didn’t add more than a couple of thousand  (I think it’s more like 3-4k\$). I’m kind of torn though. Cutting fitting and welding a tube frame is a skill I really want to acquire and having the tubing pre cut and fishmouthed seems like I’d be cheating:ermm:

10. Mar 8, 2019

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The fuselage in Solidworks is done for the Skylite and I plan to start on the Lil Bitts soon. Currently both are sidelined a bit since I am working on a rib kit at the moment for the skylite. I will have the raw material for the ribs in a few weeks and will test my new rib jig to make sure its good. Once tested I plan to sell a rib kit with the raw material pre bent to shape as long blanks but the airfoil curve will be done by the builder. It will also come with a build on top plan that serves as the Jig and include a bunch of parts to build the jig.

As for the Fuselage, if you feel like your cheating, I am also considering only having the tubes .50" and larger CNC fishmouthed. The small cross braces and such use .375" dia tubing and those are so small that the cnc fishmothing may not be necessary. For the small tubing they could be cut to size and fitted by the builder since they are the least position critical. A hybrid fuselage kit of sorts might end up being an option. As I make progress I will post in on HBA.

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11. Mar 8, 2019

### GeeZee

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That all sounds great! I’ve just been looking at the DIY bending brakes for the very purpose of bending up those rib pieces. Yes I’d be very interested in a “hybrid” tube kit, especially if it would save a little money in the process.
Also, it’s a ways off but what are your thoughts (well anyone’s) on the landing gear options. The plans show a ridged gear but it wouldn’t be too hard to turn them into a cub type bungee gear. The plans also mention an aluminum spring gear option but have no details (material, thickness, shape, etc.). Maybe you could flesh out those details when you are doing the CAD drawings.
Thanks for keeping this neat little biplane design alive!

12. Mar 8, 2019

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Have you seen the build log on the biplane forum? If not my website has a link to in the Lil Bitts info page. You can get 30 days free, but if your building one you should pay the fee and join as there is a lot of build info on there. He plans to install a spring gear like used on a Sonearai or Thatcher. He has made some progress toward that. Since he is paving new ground, whatever he comes up with will be what I will use to change or modify the plans. A spring gear is likely the easiest over the Cub type since you wont need to make provisions for the bungy. I believe he is also looking to use the O-100 DP1 engine. I will be getting one of the prototypes and have hopes to use one in a bitts one day. In regards to the ribs, I ended up making the balnks work with both the skylite and Lil Bitts. I will have a set I plan to test soon.

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13. Mar 9, 2019

### GeeZee

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Yes, I was following lakeracer’s build log before they abruptly went pay only. I was planning to pay up when I actually committed to building a Bitts ( meaning buying rib widgets and or rib parts from you). I’m leaning towards going with the spring gear as well. I really like the look of the ridged gear but I’m guessing it’s a result of going for the lightest weight possible. As I recall the very first iteration of the Bitts was as a legal ultralight (quickly abandoned by Ed). I could get started on the ribs any time but it will late summer before I could start on any big pieces. Also I was hoping you could talk lakeracer into moving his build log to your dedicated forum....

14. Mar 9, 2019

### Tiger Tim

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Genuinely curious: what's the advantage of a Li'l Bitts over a real S-1C?

15. Mar 9, 2019

### mcrae0104

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Smaller, lighter, cheaper? Compare specs here and here.

16. Mar 9, 2019

### GeeZee

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Good question. I can only answer for my reasons.
1. Stall speed, particularly as it relates to landings. A real Pitts is a handfull for most. Even experienced TW pilots say they can’t consistently get them right. I’ve read over the years that a lot of Pitts don’t get flown much because the owners are afraid of them. Things will happen a lot slower in a Bitts. I don’t currently have a TW endorsement so for me a less twitchy slower landing plane will hopefully keep me out of the bean field.
2. Fits into Light sport category. Might be important to some.
3. Should be cheaper to build, at least comparing apples to apples as much as possible i.e. new lyc to O-100 or even verner radial.
4. Fuel consumption should be lower. I will admit that in the big scheme of aircraft ownership fuel costs are almost in the noise.
So to sum up, the Bitts is a more docile aircraft but still capable of gentleman’s aerobatics and will allow the use of some interesting non- lycoming engines.

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17. Mar 9, 2019

### BJC

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We tell people that to make them think that we are superior pilots.

The reality is that a Pitts lands differently from a Champ or J-3, but if you learn the proper technique, they are straight forward to land. But yes, the round wing versions do land at a high speed compared to lots of other airplanes. Just keep the weight down; with a metal prop and an armstrong starter, an O-360 S-1S should be under 750 pounds. An S-1C / D will weigh less, land slower, climb and cruise faster.

By the time you build a Pitts, it, too will be covered by something similar to a LS category. Remember, too, Basic Med now is active.

I don’t know about the cost of a set of wires for the Bitts, but a Pitts with any rebuilt or high time Lycoming over 135 HP has a lot more aerobatic capability, so the cost differential depends on the cost of wires plus your ability to find a good rebuilt Lycoming and prop verses a Rotax and prop. The Verner is not an aerobatic engine, but it looks good and sounds good.

Yup, fuel cost is way down the list of costs of ownership. You can do lots of aerobatics for 5 to 7 gallons in an O-360.

Definitely your choice. I have nothing against the Bitts, and I’m not trying to influence your decision; just trying to share some thoughts and experience with the Pitts.

BJC

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18. Mar 9, 2019

### GeeZee

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Thanks for the well thought out response. I figured I’d hear from some Pitts drivers
I’m a 600hr pilot with a grand total of 2.7hrs of TW instruction. I’m actually just looking for a neat little open cockpit bipe to cruise around in on summer evenings and hit the occasional pancake breakfast. That the Bitts is stressed for mild acro is just icing on the cake but at present I have no interest in that, well ok maybe I’d try a aileron roll someday but aerobatics of any kind is way down the priority list.
Also, I beleve the Bitts uses round wires to keep the cost down. Not sure what an O-100 kit will end up costing but it could provide the means to have a very economical build. Me, I’m still lusting for the Verner.....

19. Mar 10, 2019

### BJC

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A unique scaled replica of a Pitts
with a Verner.

BJC

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20. Mar 10, 2019

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