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Huffy01
09-12-2009, 01:58 PM
Is there much performance difference between Biplane/Monoplane.
After playing my Phoenix Simulator practicing aerobatic's I'm thinking of buying/building something.
I'm thinking of an Ultimate Biplane but I lack flying experience's .
:<:

Huffy01
09-14-2009, 06:04 AM
Anyone know if biplanes have stalling problem and are more difficult to land than a monoplane?

EDFrules
09-14-2009, 06:11 AM
From what I've learned playing around with mono's and bipe's-yes there are differences in performance. For 3D bipes, they usually tend to be a little draggier and slower which is good for downlines. Also a lot of bipes tend to be a little "twitchier" in the roll axis with the added weight of 2 wings making a little more difficult to stop during rolls. Not a totally bad thing, just something to be aware of and try and apply more/sooner opposite control surface input to stop it where you want it. Also bipes tend to be heavier and don't like the wind as much as a mono. The only decent small Ultimate I've seen lately is the AMR by PA. Only other one I've seen fly well is the 46% sized Hanger 9. Swept back wings and placing the fuse on bottom wing don't usually go well with harriers and inverted work. A lot of bipes tend to have coupling issues due to a few of these design factors. And a lot are too short coupled IMHO. Sebart did the right thing by stretching out their Pitts airframe and it shows in flight. Much smoother and more precise. Here's a couple of vids with basically the same planform in both flavors-mono and bipe. With proper design a bipe can be made to fly 3D as well as a mono. Granted these are only flat foamies but given the same rough planform they do perform quite similarly. Working on making both full fuse/wing/tailfeathers. Should be fun. My .02
http://www.youtube.com/watch?v=ogVjDfr9LwM
http://www.youtube.com/watch?v=UJ1Pi8nhvtE

Huffy01
09-14-2009, 07:40 AM
I'm starting to like the foam planes more and more .They look like great fun.
I thought about them more when I noticed that the weather at night was better than the day, Cold but no wind and cloudless, a night fly foamy would be nice.
I have been looking at some of the Sebart models, my favourite would be "Miss Wind S 50e" looks a little more dynamic than the "Pitts Python".
I've been looking at a website called www.superandcheap.com.au (http://www.superandcheap.com.au) they have a few model which seem okay .The biplanes are a little more expensive than the monoplanes.
I'm just "weighing up" what would be the best for me, plans and balsa or a kit?

EDFrules
09-14-2009, 09:10 PM
Sebart models are top of the line quality and flight wise. Can't go wrong there. For a throw it around the yard plane, a foamie is a great choice. See the Clik thread for some more fun DIY foamie info.
http://www.wattflyer.com/forums/showthread.php?t=21158 I'm starting to like the foam planes more and more .They look like great fun.
I thought about them more when I noticed that the weather at night was better than the day, Cold but no wind and cloudless, a night fly foamy would be nice.
I have been looking at some of the Sebart models, my favourite would be "Miss Wind S 50e" looks a little more dynamic than the "Pitts Python".
I've been looking at a website called www.superandcheap.com.au (http://www.superandcheap.com.au) they have a few model which seem okay .The biplanes are a little more expensive than the monoplanes.
I'm just "weighing up" what would be the best for me, plans and balsa or a kit?

Huffy01
09-15-2009, 03:30 PM
I sent for the Ultimate biplanes plan today on the way to the hobby store too get some glue.
I ask about electric and nitro motor's to power it . Thinking that a nitro motor might be cheaper , I was pointed to a trainer plane which had a 40 size electric motor which I now own.
I only went in to get some glue which they were out of stock.

idealhobbies
09-15-2009, 04:58 PM
That's usually the way it happens. I don't think that I have EVER come out of the hobby shop with only what I went there for.

BTW... in the long run, electric is a whole lot cheaper.

I have a Multiplex Gemini Biplane and it flies quite a bit different than any of my other single wing aircraft. It rolls extremely fast, cut's quickly, and tumbles great. Now.... the wind and thermals have a greater effect on it than they do my single wings. I've had thermals knock it out of the air from 20 feet up, I've had it sent straight up in the air, and the wind has done some interesting things with it too.

Would I buy it again? Absolutely! It's a fun plane to fly. I had it over powered with a Power 10 and ended up dropping down to a Park 480 with a 11x7 prop. I'm currently experimenting with a TGY AerodriveXp SK Series 35-36 910Kv / 310w with a 13x6.5 Xoar wood prop. I'm waiting to do the maiden on that set up. I was very happy with the Park 480, but I needed it for another aircraft, so I switched out to give the 35-36 a try (since I had it in the box). If I'm not as happy with it, I'll pick up another Park 480.

Huffy01
09-15-2009, 05:40 PM
The trainer I bought today has a turnigy C4250 700kv, 5cell 3850, 25c,50c burst.
I don't know about the ESC and BEC all I can see is that it has a heatsink mounted on the ESC and both wrapped in yellow heatshrink .
I got a free flight battery with it.
If the weathers good I'll post a pic of it .

Huffy01
09-17-2009, 07:17 PM
This is the plane I have bought. It an x-nitro buy the look of the inside of the nose. It looks like the paint job didn't work ,the firewall plywood is starting to peel and in other places the wood has broken and repaired.
It has a Turnigy 4250-700, which is turning a 13x6.5th propeller.
The ESC is a mystery it has a heatsink on the top and has a UBEC attached too it. 18.5 volt, 5 cell , 3850mah battery.
3 Spektrum DS21 servos as well.
All for $250au with a free flight battery and 3.5mm connector's .
The whole plane weighs about 2272grams about 80oz.
I have been told the plane harrier's and prop hang's.
With the wind being so strong ,I've been remounting servo's, pushrods and making a battery holder.
At least I can fly something before I start building :D

Huffy01
09-21-2009, 04:46 PM
When I started my ultralight aircraft license. I saw a well known stunt pilot pratising, I can't quite remember his name but my mother can remember see him fly at shows.
He was flying a silver Pitts, it roared. Vertical spin to a stall then over the top into a positive spin and then a corkscrew the lenght of the field.
It sounded like it was going flat-out all the time until it landed.
By the time he landed the owner of the ultralight school jumped into his cessna and was doing the same right over the school.
Nothing like the feeling of watching a cessna doing a positve spin right above you, like its heading for your nose.

Mr Wizard
09-23-2009, 04:52 AM
Bibes: More wing area for span, thus, as a rule, can do faster spins and not lose on landing speed. Draggier, but that's a good thing for showy tight low show flying...

As mentioned above, they tend to be short coupled...but, if you are an experienced flyer or don't tend to drink three cups of java before flying, no trouble there. They will porpoise on you very quickly if you over control.

Bipes are sturdy, but, a pain to fix once you prang them.

If you just love making wings, bipes are your plane

Monos: sleeker, a bit faster for the same power/weight, can have the same wing area as a bipe without too much awkward looking aspect ratio. With modern material, wings can be made strong enough to take just about any maneuver without strings and braces...so cleaner looking.

But, there is something thrilling and somehow seems at the heart of flying that bipes capture that monos just don't.

Huffy01
09-25-2009, 04:07 PM
I received the Ultimate Biplane plans in the post today!

Gimpster
10-07-2009, 02:09 AM
One thing to be careful of with the Ultimate is the CoG. I had mine set as per the manufactures instructions but it ended up being a fare bit nose heavy, which resulted in a fast and sensitive plane with very poor stall habits and very little control surface authority when off power. It nosed in hard on it's third outing and a fellow club member discovered the correct CoG was far more aft then I had mine set at. I still prefer a monoplane for 3D but thats just me.

Huffy01
10-07-2009, 10:32 AM
Here's a link to the construction article in Airborne magazine. www.airbornemagazine.com.au/artBiPla.htm (http://www.airbornemagazine.com.au/artBiPla.htm)
Most of my time lately I have been spending photo copying plans so I can start cutting out parts.
The c.g. on this plane sems to be further forward. I thought it would be further back because of the sweep in the wing?

Gimpster
10-08-2009, 01:55 AM
That's the issue I had with mine. Before you fly it find someone with a program to calculate the correct CoG from the actual weights and measurements if you want to be sure about the correct CoG. As far as flying characteristics, mine with the CoG forward was fast and very pitch sensitive. It did some nice high speed aerobatics but did not like to slow down at all which made slow speed aerobatics and landings a bit nerve wracking.

Based on my club mates calculations the CoG should have been some where about 2/3 of the way back from the leading edge of top wing, measured at the center line of the wing. I don't have an exact number and I am sure it will vary by model as they are not all the same.

rcplaneguy1
10-08-2009, 03:43 AM
well, monoplanes aren't quiet as aerobatic as bipes, but it all depends on a high or low level wing monoplane.

dsmmike
10-08-2009, 06:37 AM
From what I've learned playing around with mono's and bipe's-yes there are differences in performance. For 3D bipes, they usually tend to be a little draggier and slower which is good for downlines. Also a lot of bipes tend to be a little "twitchier" in the roll axis with the added weight of 2 wings making a little more difficult to stop during rolls. Not a totally bad thing, just something to be aware of and try and apply more/sooner opposite control surface input to stop it where you want it. Also bipes tend to be heavier and don't like the wind as much as a mono. The only decent small Ultimate I've seen lately is the AMR by PA. Only other one I've seen fly well is the 46% sized Hanger 9. Swept back wings and placing the fuse on bottom wing don't usually go well with harriers and inverted work. A lot of bipes tend to have coupling issues due to a few of these design factors. And a lot are too short coupled IMHO. Sebart did the right thing by stretching out their Pitts airframe and it shows in flight. Much smoother and more precise. Here's a couple of vids with basically the same planform in both flavors-mono and bipe. With proper design a bipe can be made to fly 3D as well as a mono. Granted these are only flat foamies but given the same rough planform they do perform quite similarly. Working on making both full fuse/wing/tailfeathers. Should be fun. My .02
http://www.youtube.com/watch?v=ogVjDfr9LwM
http://www.youtube.com/watch?v=UJ1Pi8nhvtE
do you know what plans you used for that bipe? or was it a kit. it looks very similair to some plans im about to build a bipe from, and could use some input

Huffy01
10-08-2009, 09:27 AM
i just pulled the plans out for my Ultimate Biplane. Both wings are the same with a chord length of 200mm. The c.g point on the top wing is about 90mm from the leading edge. If I draw a line straight down it is only about 10mm from the leading edge of the bottom wing.
I can only guess that the c.g is found with a balance between the aerodynamic lift of the wing's.

EDFrules
10-08-2009, 04:35 PM
My friend Blake challenged me to come up with a pattern/3D bipe with no coupling issues. Bipe-X was born. A few months later there was a look a like bipe kitted by someone else. OK though, it don't fly as good as mine! hahahaha. I was going to sell the plans but instead have decided to have some kits produced. My CNC guy is working on the first cutouts now so should be available soon. Most other bipes tend to plop the fuse on the bottom wing and not make anything symmetrical as far as wing placement(staggering) or additional rudder below the thrust line. This usually results in quite a bit of coupling. Not what we were looking for. And most bipes tend to be really short coupled, not good for tracking either. I noticed that the new crop of pattern bipes coming out soon have a more or less symmetrical wing/fuse layout proving my theory. Treat the airframe symmerically and she'll fly that way! Good luck with your build and stay tuned for more Bipe-X developments.

Jason do you know what plans you used for that bipe? or was it a kit. it looks very similair to some plans im about to build a bipe from, and could use some input

Huffy01
10-08-2009, 05:04 PM
I've got to ask ," what is coupling" and what problem occurs when you have coupling?

EDFrules
10-08-2009, 05:37 PM
Coupling is when your plane rolls into knife edge flight and wants to pull to the canopy or push to the gear. Meaning it doesn't want to track straight during KE. This can be sometimes mixed out with some rudder/elevator mixing on your radio. I'd prefer not to do any of that and have a plane that handles neutrally in all axis'. In any of the vids we've done on it there is no mixing on the radio to make it fly right-zero. Sweet! Most bipes end up with sometimes over 10% rudder/elevator mix and this screams "I've got lots of coupling-please mix me out!" Also a longer tail moment helps in that dept. Made a shorter coupled Bipe-X just for testing and it didn't handle nearly as well as the longer version-point taken. Ulitmates usually have quite a bit of coupling(which helps with snaps but little else). I think the common mistake is trying to make a scale aerobatic bipe and try and make a scaled down version of it do 3D-what it's not designed to do. Then you've got to redesign it to work out all its bad habits. I told my friend when I started this project not to expect the usual bipe. I started with a blank sheet of paper and extrapolated from previous experience with monos as to what worked and didn't. There's no wing rock either which I love-just pull back on the elevator and chop the throttle-she'll come straight down with no rock-NIce!

Gimpster
10-09-2009, 05:19 AM
The only thing I don't like about most of the planes out there that are designed to be free of coupling issues, is that they tend to be very symmetrical which is just the results of form following function. I tend to find it difficult to retain orientation on them because in profile they look the same upright as they do inverted, with only color patterns being used for visual orientation reference.

I have a small 24" bipe called the CTC, it's an 8oz Ripstop cloth and CF rod profile bipe. The plane is nearly symmetrical with the vertical stabilizer/rudder being the only asymmetrical feature. While this plane does excel at 3D I loose orientation with it very easily. I think the real trick is going to be in trying to find a way to retain an asymmetrical visual/physical profile while still retaining a symmetrical aerodynamic profile.

I think part of the issue is that we are running single propellers which require a thrust line that is offset from the center line of aircraft. The only way around that is to run an inline counter rotating prop setup, which is unfortunately a very complex mechanism, or twin counter rotating engines. That only eliminates one of the issues though. We are still left with the issue of making an asymmetrical shape with symmetrical aerodynamics, if that is even possible.

But none of this really makes a difference in whether to choose a mono plane or a biplane does it?

EDFrules
10-09-2009, 07:48 AM
My Bipe-X has just enough asymmetry built in to make it discernible in flight no matter the orientation. And of course a easily identifiable paint scheme so I know which side is which. Plue the landing gear is a dead giveaway! I'm not a big fan of the Tensor look either for the same reasons. When I get the full fuse/wing/stab version done it will be a lot easier to figure which end is up. From what I've seen of the new gen pattern bipes coming out it's not really an issue of orientation anymore. They need a little off center asymmetry built in for snaps anyway. The Shark looks like a good 3D/hybrid candidate with some different wings and surfaces:DThe only thing I don't like about most of the planes out there that are designed to be free of coupling issues, is that they tend to be very symmetrical which is just the results of form following function. I tend to find it difficult to retain orientation on them because in profile they look the same upright as they do inverted, with only color patterns being used for visual orientation reference. My motor thrust line is dead center between the wings and the elevator right on the thrust line. Seems to work well. The only problem with counter rotating props is they tend to be too small dia. for 3D work. They've been tried before and don't seem to work for 3D. Pattern is another story. See the new Miss Wind S bipe from Sebart. Uber special Hacker powered gearbox with huge props. Sebastiano couldn't seem to make it fly fast enough in one of the events! Zero'd out as he couldn't complete the rountine in time. Ooops. Think that's been worked out now. Certainly practical for pattern but for torque rolls and such counter rotating props seem to not help out.

I have a small 24" bipe called the CTC, it's an 8oz Ripstop cloth and CF rod profile bipe. The plane is nearly symmetrical with the vertical stabilizer/rudder being the only asymmetrical feature. While this plane does excel at 3D I loose orientation with it very easily. I think the real trick is going to be in trying to find a way to retain an asymmetrical visual/physical profile while still retaining a symmetrical aerodynamic profile.

I think part of the issue is that we are running single propellers which require a thrust line that is offset from the center line of aircraft. The only way around that is to run an inline counter rotating prop setup, which is unfortunately a very complex mechanism, or twin counter rotating engines. That only eliminates one of the issues though. We are still left with the issue of making an asymmetrical shape with symmetrical aerodynamics, if that is even possible.

But none of this really makes a difference in whether to choose a mono plane or a biplane does it?

Gimpster
10-15-2009, 03:17 AM
That sir is a real looker. Very nice indeed.

When can I get one?

EDFrules
10-15-2009, 05:46 AM
This is prototype from what I understand. When they do become available, Oxai Models will surely carry them. They only make the best FAI planes in the world.:$ So if you have to ask how much they are-you can't afford! LOL Seriously, if you want Narauke-San to build you one-get in line and shell over 10k per plane(RTF). You have to ship over a radio for your order and your plane will be perfectly built-flight tested and mixes put on your radio. When you fly it-if it's not right, it's the pilots fault! Otherwise I would expect the kit to sell for about 2-3K-that's not including shipping. Here's the site:
http://www.oxai-rc.com/main/List.aspx?MID=1

MIss Wind S bipe would be a more available choice. The 50 sized version is available soon thru Eprit Models:
http://www.espritmodel.com/index.asp?PageAction=VIEWPROD&ProdID=11379
$380 plus shipping soon. I know my bud Blake would love to get his hands on the 110 sized version.