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Pumpkin drop event

Two Plane Build Projects

Chuppster

Well-known member
#41
@Chuppster if you know guys who build a tandem B-52, invite them here to this discussion and study, it be great to have their words of wisdom too. Thanks.
I'm pretty sure you're pioneering the large-scale tandem wing. I can't say I've seen many designs that use it because of the issues, such as difficulty to control, extra drag, and double the materials of a single wing.
 
#42
I'm pretty sure you're pioneering the large-scale tandem wing. I can't say I've seen many designs that use it because of the issues, such as difficulty to control, extra drag, and double the materials of a single wing.
yeah, watching the Mig-3 DIY build to see how to strengthen the wings, how should the wings be built for bomber, something like how Josh is building the Mig wings? I am hoping @flitetest would come to our local airport in Oakley Kansas and do a Flite Fest there, we had the paramotor guys who used the frame like a go-cart and parachute to fly, that was awesome so, it be awesome to bring the bomber and the champ to show everyone. @Chuppster

yeah, I am pioneering this, well we belong to the Flite Test family, so nothing wrong with testing. On the idea of moving it, incase Flite Fest comes to town, should the wings be one large thing or attach?
 

DamoRC

Well-known member
Mentor
#43
yeah, I am pioneering this, well we belong to the Flite Test family, so nothing wrong with testing.
Absolutely! That's what we do 'round here. Perhaps, however, your are trying to fly before you can run before you can walk? This sounds like an awesomely ambitious project for any builder.

how should the wings be built for bomber, something like how Josh is building the Mig wings?
The Mig wing design and build is a great approach for a wing of that wingspan and shape and would be a solid basis for a wing for any type of plane that has approximately the same span.

But it sounds like you are aiming for something a little more challenging? I read earlier that you wanted to build the tandem B-52 a tad bigger than Horseman's B-36 which had a wingspan of 6' 4". So are you thinking 7 feet? Perhaps 8 feet? The reason I ask is that at some point in the thought process around this design you will need to make some decisions which, once made, inform and drive the next set of questions and decisions and initial decisions on things like wingspan can lead to quickly getting answers to other questions.
For example, you asked earlier if the wing should be detachable or not. If you decide to build it with a 40 inch span then the answer is probably "No" because you should be able to fit it into most cars. If you decide to build it with an 8 foot wingspan then the answer to the detachable wing is "Yes" (unless you have a pretty large vehicle to transport the plane in).

Why don't we start with the wingspan and then we can work our way forward from there?

DamoRC
 
#44
Absolutely! That's what we do 'round here. Perhaps, however, your are trying to fly before you can run before you can walk? This sounds like an awesomely ambitious project for any builder.



The Mig wing design and build is a great approach for a wing of that wingspan and shape and would be a solid basis for a wing for any type of plane that has approximately the same span.

But it sounds like you are aiming for something a little more challenging? I read earlier that you wanted to build the tandem B-52 a tad bigger than Horseman's B-36 which had a wingspan of 6' 4". So are you thinking 7 feet? Perhaps 8 feet? The reason I ask is that at some point in the thought process around this design you will need to make some decisions which, once made, inform and drive the next set of questions and decisions and initial decisions on things like wingspan can lead to quickly getting answers to other questions.
For example, you asked earlier if the wing should be detachable or not. If you decide to build it with a 40 inch span then the answer is probably "No" because you should be able to fit it into most cars. If you decide to build it with an 8 foot wingspan then the answer to the detachable wing is "Yes" (unless you have a pretty large vehicle to transport the plane in).

Why don't we start with the wingspan and then we can work our way forward from there?

DamoRC
wow, yeah I must of missed that part in the read on @Horseman3381 build, the wing size I believe is big enough for me, I was thinking the a little more meat added to the body, where it is a tad bigger in that area, should of said that better. 6' 4'' is the wing span, dang that is the height of my dad, wow, okay that will be long enough. what size is the body of the B-36? @DamoRC I will go back and re-read it for myself also. So how big is a sheet of foam board? are paint sticks to small for a 6' 4'' wing brace or would the thickness of a yard stick be just right, same shape of a paint stick. @sprzout @Chuppster

@DamoRC I am just learning here and figuring out how to fix what I designed with very weak cardboard paper towel rolls.
 

DamoRC

Well-known member
Mentor
#45
Okay, 6'4" is a starting point. With this wingspan, the overall length will be ~62 inches. The pods will be 3 inches in diameter (so they could take one 70mm EDF or two 30-35 mm EDFs and the maximum width of the fuselage will be almost 4 inches.

A sheet of foamboard is 20 inches by 30 inches. At 6'4" wings and tailfeathers are going to take 3-4 sheets of foam board.

You won't be able to brace this wing with a paint stick spar but the yardsticks you get at Home Depot for a buck might work (might need more than one).



Initial Measurments.jpg

DamoRC
 
#46
Okay, 6'4" is a starting point. With this wingspan, the overall length will be ~62 inches. The pods will be 3 inches in diameter (so they could take one 70mm EDF or two 30-35 mm EDFs and the maximum width of the fuselage will be almost 4 inches.

A sheet of foamboard is 20 inches by 30 inches. At 6'4" wings and tailfeathers are going to take 3-4 sheets of foam board.

You won't be able to brace this wing with a paint stick spar but the yardsticks you get at Home Depot for a buck might work (might need more than one).



View attachment 112104

DamoRC
Thanks @DamoRC just learned Dollar General has the foam board, hopefully our DG in Oakley has the foam board, we will be checking.
 
#48
Okay, 6'4" is a starting point. With this wingspan, the overall length will be ~62 inches. The pods will be 3 inches in diameter (so they could take one 70mm EDF or two 30-35 mm EDFs and the maximum width of the fuselage will be almost 4 inches.

A sheet of foamboard is 20 inches by 30 inches. At 6'4" wings and tailfeathers are going to take 3-4 sheets of foam board.

You won't be able to brace this wing with a paint stick spar but the yardsticks you get at Home Depot for a buck might work (might need more than one).



View attachment 112104

DamoRC
On the 70mm EDFs are pretty good price of $35.79 on hobby king.
 

Chuppster

Well-known member
#49
On the 70mm EDFs are pretty good price of $35.79 on hobby king.
Can you link that? I don't think HK sells a 70mm EDF for that cheap.

A popular 70mm EDF around here is this one from Motion Rc.
It needs a 70a esc. So, for some quick math,

4x EDF @ $40
4x ESC @ $20
4x 4s 3000mah @ $20

That's $320 in electronics alone. We haven't even gotten started with wiring, tx/rx, landing gear, servos.....

We could cut costs with a cheaper EDF.

This will give you less thrust but cut your cost by $80. Still, that sets you at $240.

Before I start a project I like to count the cost before I start drawing any plans. I recommend you do so as well. I'm not trying to discourage you from building this bird, however, I will say that you can build a lot of FT planes for $300, and crashing a $50 airplane feels a whole lot less devastating than crashing a $300 one. I believe that you can do this if you set your mind to it, but the best/least expensive route may be to start out in the hobby with bite-sized pieces. Perhaps design a mighty-mini B-52 that uses a little pusher prop on the back. Say, 30" wingspan? That way you can start with a build that doesn't require fancy materials to make sturdy or is difficult to repair on a crash.

I have been in the hobby now for almost a year and I have enjoyed building other people's designs. I learn from each one, from the Simple Cub to the X-29. If building from plans isn't your style I can respect that. I have found, however, that it is much less time consuming, frustrating, and disheartening to take someone else's plans and re-create what they have built. It may be less satisfying but at least there's less chance for failure. The last thing I want to see is for you to get all excited and into the hobby, hit a tough road block, get discouraged, and quit. I think that can happen to a lot of people and we want you to stick around.

Just my $0.02
 

DamoRC

Well-known member
Mentor
#50
On the 70mm EDFs are pretty good price of $35.79 on hobby king.
Cool - which ones (can you post the link)?

Remember, to build just the regular B52 you'll need 4 of these (one in each pod), 4 ESCs (probably 60A), and batteries. You will probably need four 4S batteries in the 1800mAh to 2200mAh range. You can go with fewer batteries of higher capacity but then they will probably only every be useful for bigger builds.

Do you have a lipo balancer / charger and a lipo checker?

You'll need pretty sturdy servos (the 9 gram FT ones probably wont cut it for this size build)

DamoRC

p.s. - Do you have access to a laptop / computer? Probably be useful for the design / calculation / measurement work that you will need to do (like the dimension stuff I did above with Sketchup).

DamoRC

EDIT - oops , hit post and then saw @Chuppster's reply. Agree, on my more advanced projects I try to lock basic dimensions etc early so I can work out the budget, or if I have the parts already, or if I have to strip (or, ahem, crash and strip) one of my other planes.
 
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Hai-Lee

Old and Bold RC PILOT
#52
I have a few concerns which I wish to air and if I am wrong please take them as advice only on the subject of Tandem wing designs.

Firstly if you cannot pilot an RD model competently then do not try to learn on a tandem wing design.

Tandem wing designs are rare simply because of the airflow interference from the front wing severely and adversely effecting the rear wing. Most tandem wing designs are notorious for their control instability. One simple way to help overcome the instability is to ensure that the 2 wings are separated by as much as distance as is possible and in addition the rear wing MUST not be one the same level or below the front wing.

Even with Tandem rotor helicopters the rear rotor disk is above the front rotor disk to help it operate in relatively undisturbed air. When ailerons or similar are operated the airflow over the front wing is altered and if too close also on the rear wing leading edge. This can actually lead to the stall of the rear wing just doing a simple aileron turn.

On a tail unit close and inline with the main wing on a conventional aircraft the disturbed airflow has minor effect due to the physical distance between the wing and tail but also because of the simple fact that the tail is lightly loaded if loaded at all. If the tail is heavily loaded, (aircraft is very tail heavy), the effects of maneuvering can be disastrous, including total loss of control altogether.

As the incident angle of the airflow between the front and rear wing are different, (if the tandem wings are on the same level), calculating the ideal CG point can be extremely difficult and it can even vary depending on the speed and control inputs.

Good luck with your experiment but I advise against spending money unless you have the design and what you wish to test firmly established beforehand.

Have fun!
 
#53
Cool - which ones (can you post the link)?

Remember, to build just the regular B52 you'll need 4 of these (one in each pod), 4 ESCs (probably 60A), and batteries. You will probably need four 4S batteries in the 1800mAh to 2200mAh range. You can go with fewer batteries of higher capacity but then they will probably only every be useful for bigger builds.

Do you have a lipo balancer / charger and a lipo checker?

You'll need pretty sturdy servos (the 9 gram FT ones probably wont cut it for this size build)

DamoRC

p.s. - Do you have access to a laptop / computer? Probably be useful for the design / calculation / measurement work that you will need to do (like the dimension stuff I did above with Sketchup).

DamoRC

EDIT - oops , hit post and then saw @Chuppster's reply. Agree, on my more advanced projects I try to lock basic dimensions etc early so I can work out the budget, or if I have the parts already, or if I have to strip (or, ahem, crash and strip) one of my other planes.
Yeah, this is from Hobby King the Dr. Mad Thrust 2200KV 1600 W 70mm
info on this engine below in image. Thanks Hai-Lee on your two cents, good info and advice.

@DamoRC @Chuppster @Hai-Lee
 

Attachments

#54
I have never heard of that engine, must be branspanking new, if you know it, let me know, it be cheap, has a lot of get up and go. yeah will be looking at the parts list, our super walmart has wood skewers cheap and a bundle, also rolls of boxing tape cheap too, if our dollar general has the foam board, that be good, if these engines are good and no problems, then that is good for a EDF, now the electronics needed, plus the wheels.
 

DamoRC

Well-known member
Mentor
#56
Yeah, this is from Hobby King the Dr. Mad Thrust 2200KV 1600 W 70mm
info on this engine below in image. Thanks Hai-Lee on your two cents, good info and advice.

@DamoRC @Chuppster @Hai-Lee
The link you posted is just for the motor. You need the fan unit also (which is another $15) and this combo requires a 100A ESC! That's going to get you close to $80 or $90 for the bundle (so close to $400 for the motors and ESCs). Also it runs on 6S. Agree with Hai-Lee, that at this stage, spending that kind of money is probably nuts.

Look for a 70mm EDF unit that runs on 4S in the $30 dollar range that can use a 60 or 80 amp ESC. (The one @Chuppster linked to is a pretty good match). Look at the thrust numbers for it because that is going to inform what the max weight of the plane could be.

DamoRC
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#57
As the incident angle of the airflow between the front and rear wing are different, (if the tandem wings are on the same level), calculating the ideal CG point can be extremely difficult and it can even vary depending on the speed and control inputs.

This... Your CG shifts mid-flight and your plane can become tail heavy depending on pitch and speed... Impossible to fly.

Been following this thread and I'm with Hai-Lee on it. This build is for a sponsored (rich), experienced (has their own shop and 10,000 hours build time) kinda guy and will take 18 - 24 months if it is to fly and be RC.

If you wanna experiment on tandem wings, I would chop up a Tiny Trainer and play at the $25 level rather than play at the $500 level with a big bomber.
 
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#58
This... Your CG shifts mid-flight and your plane can become tail heavy depending on pitch and speed... Impossible to fly.

Been following this thread and I'm with Hai-Lee on it. This build is for a sponsored (rich), experienced (has their own shop and 10,000 hours build time) kinda guy and will take 18 - 24 months if it is to fly and be RC.

If you wanna experiment on tandem wings, I would chop up a Tiny Trainer and play at the $25 level rather than play at the $500 level with a big bomber.
sounds good. thanks everyone and you're right @Chuppster , question for the rich and mighty, why do u guys have all the fun and can build awesome experimental aircraft? okay, that breaks my spirits, but after I'm done with the Champ, will experiment with it.
 

Chuppster

Well-known member
#59
sounds good. thanks everyone and you're right @Chuppster , question for the rich and mighty, why do u guys have all the fun and can build awesome experimental aircraft? okay, that breaks my spirits, but after I'm done with the Champ, will experiment with it.
You can build experimental aircraft too! Just maybe don't learn to swim in the deep end of the pool? Don't be discouraged, be inspired! Print out a 3-view of the B-52 to the scale you want and hang it on the wall, then look at it every day as your work your way up in skill and experience. If you persevere you can get there. But like anything in life you have to get good experience with the basics before you can become proficient at what you're doing.

If you wanna experiment on tandem wings, I would chop up a Tiny Trainer and play at the $25 level rather than play at the $500 level with a big bomber.
This is a great idea. When you venture into the unknown (tandem wing design) you should start by changing up something that's known (a proven design). That way you're not trying to figure out too much at once.
 
#60
You can build experimental aircraft too! Just maybe don't learn to swim in the deep end of the pool? Don't be discouraged, be inspired! Print out a 3-view of the B-52 to the scale you want and hang it on the wall, then look at it every day as your work your way up in skill and experience. If you persevere you can get there. But like anything in life you have to get good experience with the basics before you can become proficient at what you're doing.



This is a great idea. When you venture into the unknown (tandem wing design) you should start by changing up something that's known (a proven design). That way you're not trying to figure out too much at once.
man, brings me to another memory, the life guards at the community pool when I was little, actually taught us to swim, yep in the deep end, yeah so I guess I did as I was taught, as you said, "learning to swim in the deep end", will print out as you suggest, if the champ needs a new wing, will see if I can transfer the electronics into a tandem wing design. then go from there @Chuppster @DamoRC