Baby Bugatti 700m

lawrenceyy

New member
Baby Bugatti 700mm

I thought I'd give back to the community and post my plans and procedures for a 700mm wingspan Baby Bugatti. I would like to give a special thanks to Ben Harber (Mid7night) for the original design, but it was too small for my components. My evolution of the Baby Bugatti is 40% larger (wingspan comparable to FT Sparrow). I have flown it a few times already and boy does it fly well– it tracks very straight, rolls on center, and can fly at high and low speeds.

My plans were drafted and color-coded for laser cutting, so they do not follow Dan Sponholz's CAD standards. My procedure is well documented, so it is clear where to bevel cut and where to remove foam. The plans use 1.5 pieces of foam board (or you can fit two complete sets on three full sheets). My design also features a top hatch that makes accessing the battery and other components much easier.

View attachment 170731 Baby Bugatti Plans.pdf

View attachment 170813 Baby Bugatti Plans_Tiled.pdf

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PsyBorg

Wake up! Time to fly!
Clean build and a great job with the detailed and annotated pictures. That will help a lot of people learn how FT style building is done and how clean things should be when the project is finished. This is worthy of a little more detailed step by step instructions to go with these pics and be made into an article. :applause:
 

rockyboy

Skill Collector
Mentor
Very nicely done sir! You've given all the people in the WW2 challenge a clear target for build instruction clarity. I'll be using this post as the standard for scoring.

All that's missing is a banana for scale :p
 

cranialrectosis

Faster than a speeding face plant!
Mentor
This could/should be an article it is so well presented. Nice job! :)

Got any video of the plane in the air?
 

lawrenceyy

New member
Very nice level of detail. What size motor are you running?

I've been flying it with a Emax MT 2204 2300kV, but I want more speed so I'll be swapping it out for a Emax RS 2205s 2300kv. The KV is the same for both motors and the recommended props are the same too, but the specs say that one puts out considerably more thrust than the other. If the rotation frequency of the motor is related to the voltage, shouldn't both have the same max rotation speed (using the same battery) and therefore produce the same thrust (using a similar prop)? I've marked out where the two have similar RPM but greatly different thrust.

MT2204:
MT2204-specification-2.png

RS2205s:
71ehUA29kbL._SL1203_.png
 
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lawrenceyy

New member
Does anyone know the answer to my question in the previous post?

When I take my Baby Bugatti out to fly this weekend with the new motor, I'll try to get some videos to share.

2017-08-03 18.48.04.png

2017-08-03 18.48.30.png
 
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MrFowl

New member
I'm pretty sure one is a 5x3 prop, and the other is a 5x4.5 prop. Which means for one revolution, the higher pitched prop (5x4.5) will (theoretically) travel 1.5 inches further. This will most likely mean the motor is using more power. The voltage will be the same, but it will be pulling more amps (P = I * V). At 2300kv, and 12v, that's quite a lot further per minute.
 

lawrenceyy

New member
I was running a 5x4.5 prop on the MT2204 before. I currently have the same 5x4.5 prop on the RS2205s. Does this mean that I'm not going to see a performance difference? What motor and prop combo should I go with to make this thing go fast (preferably a prop not larger than 5" or 6" because it won't be to scale with the plane)?
 

MrFowl

New member
Okay, I did a little more research and it seems the rs2205s has stronger magnets and tighter tolerances. If you have a 4s you can stick in there with a 5x4.5 prop it should make about 1000g of thrust. It will be pulling about 30-35amps though... So a 40-45A esc or higher would be needed. BTW, those rs2205s motors are amazing.

If you stick with 3s, you will probably see longer flight times and maybe a little faster top speed. If you can get a 5x5 prop that will give you about 10-15mph more, but also cut down on your flight time. The prop will most likely be stalled at 0 airspeed too, so a hard toss would be needed to get it flying. On 3s with a 5x5 prop I would say you should still use a 20-25A esc minimum.

If someone catches a mistake, please correct me! (I'm not 100% sure I'm right about all this)
 

lawrenceyy

New member
The video is from this morning and was taken by one of the leaders in our group.


I did not observe any significant increase in the speed of the plane. Battery life was about the same (3-4 minutes on a 3s 500mah), though the voltage alarm starts beeping about 10 seconds in if I go full throttle after take off. I've already got a 30A ESC in this plane. Currently, there is a tri-prop mounted to the motor. The downside is that at rest, the front of the plane is actually held up by the prop since the fuselage is not very tall. I was at the hobbyshop before reading MrFowl's post and picked up a two-bladed 6x4E prop.
 
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Mid7night

Jetman
Mentor
The video is from this morning and was taken by one of the leaders in our group.


I did not observe any significant increase in the speed of the plane. I've already got a 30A ESC in this plane. Currently, there is a tri-prop mounted to the motor. The downside is that at rest, the front of the plane is actually held up by the prop since the fuselage is not very tall. I was at the hobbyshop before reading MrFowl's post and picked up a two-bladed 6x4E prop.

Well, that looks like it flew downright AWESOME! Congrats! It's so great to see more people having fun with this little bird, no matter what scale. :)
 

cranialrectosis

Faster than a speeding face plant!
Mentor
Great post, lawrenceyy. What a fantastic build.

It's a Bugatti a guy like me can see for under 200 hours of build time and from the looks of it, flies great.

Thanks for this one. You made my morning! :)
 

PsyBorg

Wake up! Time to fly!
I was running a 5x4.5 prop on the MT2204 before. I currently have the same 5x4.5 prop on the RS2205s. Does this mean that I'm not going to see a performance difference? What motor and prop combo should I go with to make this thing go fast (preferably a prop not larger than 5" or 6" because it won't be to scale with the plane)?

With the same prop and same kv the 2205 will just have to work less to do the same things a 2204 can. You should not expect much of a performance change but you will see a little more efficiency and probably a slightly longer flight time. Of course when specing for efficiency the battery plays a huge part. Or if you did want a performance change you would be able to swing a higher pitched prop because the 2205 should produce a little more torque
 

lawrenceyy

New member
I had a chance to fly again today, and did notice an increase in speed with the 5x4 prop. However, I think my small 500mah 3s 25c battery is whats holding me back. It's connected via JST which I think is limiting the current, and its output quickly diminishes when at full throttle. I've already ordered a few 800mah 3s 40c with XT60 connectors. I re-watched the flitetest episode on breaking 100mph. What kind of motors/prop/esc/battery combo would I have to get nowadays to fly at those speeds? I mostly use Emax motors, but would be willing to look at other brands.

One observation: the plane has a steep-ish glide slope if the throttle is totally cut (steeper than the sparrow, but not terrible). It can fly at slower speeds, but it just needs some throttle (around 30%). I definitely needed to hold a little throttle during landing till about 3 feet off the ground.
 

SlingShot

Maneuvering With Purpose
One observation: the plane has a steep-ish glide slope if the throttle is totally cut (steeper than the sparrow, but not terrible). It can fly at slower speeds, but it just needs some throttle (around 30%). I definitely needed to hold a little throttle during landing till about 3 feet off the ground.

That sounds nose heavy...