Typhon Donut Man's Typhon GT Build

[The Donut Man]

I can't answer this question because I don't have clue what I'm doing! I do however love these threads because you guys do know what your doing. Speaking of which, you know your going to do it, get the XLX2, sounds like it's worth it.

Called me out, man! Probably just looking for validation before I switch

 

[Edough13]

Called me out, man! Probably just looking for validation before I switch

You know as well as I do if you thought about it enough to make a post you already plan on getting it
I just picked up a Lim!!! Super excited as I've been "thinking" about getting one and got a great deal! Now just need a servo, any recommendations? Not looking for top of the line but just a decent servo for it

 

[The Donut Man]

@LibertyMKiii's 200+ Or Bust project had me thinking about the aero achievable with off-the-shelf bodies, and I remembered an idea I had a while back. What if I took my Jag body and cut out the bubble "canopy" and replaced it with smooth Lexan? The center-mounted ESC wouldn't fit anymore so it would be best suited for a different chassis layout than mine, and I already like how my shell is painted. I saw Raz try it out (don't know what shell he used) sometime later and there was significantly less downforce, so that would be an issue to manage. But I'd rather try this out on a brand new shell, so I started looking on Delta Plastik's website. I found this body which is essentially the 360mm-wheelbase version of their Porsche 911 GT1 Evo. The nose profile looks great, and the top of the body looks pretty flat and easy to work with. I may end up trying this out in the summer!

The stock shell:

My modification idea:

Edit: fixed a typo

 

[LibertyMKiii]

@LibertyMKiii's 200+ Or Bust project had me thinking about the aero achievable with off-the-shelf bodies, and I remembered an idea I had a while back. What if I took my Jag body and cut out the bubble "canopy" and replaced it with smooth Lexan? The center-mounted ESC wouldn't fit anymore so it would be best suited for a different chassis layout than mine, and I already like how my shell is painted. I saw Raz try it out (don't know what shell he used) sometime later and there was significantly less downforce, so that would be an issue to manage. But I'd rather try this out on a brand new shell, so I started looking on Delta Plastik's website. I found this body which is essentially the 360mm-wheelbase version of their Porsche 911 GT1 Evo. The nose profile looks great, and the top of the body looks pretty flat and easy to work with. I may end up trying this out in the summer!

The stock shell:


My modification idea:


Edit: fixed a typo

I think this could work but you have to be careful about the end result shape. This is why Raz ran into issues.
Take a look at an airplane wing and the way it creates lift. This closely resembles the shape of the car body without the roof (where the bottom is flat and the top is an elongated curve.

You may want to take your plastic and make the car more of a wedge shape to avoid the lift that occurs. Aerodynamics gets quite complicated when you dive deep into it.

When the curve over the front wheel comes up and then back down it will create lift for the front
(Red line is bad and blue line shows airflow curve similar to the airplane wing graphic above.)

More ideal shape

 

[The Donut Man]

I think this could work but you have to be careful about the end result shape. This is why Raz ran into issues.
Take a look at an airplane wing and the way it creates lift. This closely resembles the shape of the car body without the roof (where the bottom is flat and the top is an elongated curve.

View attachment 133448

You may want to take your plastic and make the car more of a wedge shape to avoid the lift that occurs. Aerodynamics gets quite complicated when you dive deep into it.

When the curve over the front wheel comes up and then back down it will create lift for the front
(Red line is bad and blue line shows airflow curve similar to the airplane wing graphic above.)
View attachment 133449


More ideal shape

View attachment 133450

Angling whatever plastic I would add is a good thought; I had only considered tilting the entire body with tall rear body mounts. I would also fit a wing and vertical fins, but I’d like to stew on that for a while! I’m not really sure what the best shape for the rear of the shell would be. I like the idea of a long wedge tapering from the ground to the top of the shell’s profile, but I don’t want to make downforce past the rear wheel; I’m worried it would create a moment that would take weight off the front wheels and increase chances of blowing over. Here’s my initial thought (red would be bent aluminum/plastic, blue would be aluminum diffuser vanes):

Edit: so essentially I'm thinking of incorporating some Limitless diffuser parts with a handmade extension to the shell

 

[Ryambo]

I think this could work but you have to be careful about the end result shape. This is why Raz ran into issues.
Take a look at an airplane wing and the way it creates lift. This closely resembles the shape of the car body without the roof (where the bottom is flat and the top is an elongated curve.

View attachment 133448

I've followed your work on the carbon bodies, awesome work!

This baffled me 20 years ago. Having been told this as a kid, I built an RC plane with a symmetrical airfoil and found myself questioning this explanation. How did it fly when the profile at the top of the wing was identical to the bottom? This got me wondering how a plane with a conventional airfoil flies upside down. Then I started questioning how Bernoulli's principle could account for producing the amount of lift an airplane needs. For reference, the new 777-300ER max take off weight is 774,600 pounds!

I was curious, so I read a lot about this and even used this as a topic for a research paper in '02. What I found is that deflection is actually the primary source of lift. Angle of attack is critical to deflecting air and airfoils are designed to do it in a an efficient and stabile way, the relatively small pressure differential created by Bernoulli's principle is a welcome byproduct. I share this respectfully, and for nothing more than the sake of exchanging information.

https://www.grc.nasa.gov/WWW//K-12/...plane wing is shaped,the wing deflect the air.

https://www.sciencelearn.org.nz/res...i's principle, the,air become more spread out.

 

[rotauq]

I've done several prototypes without a canopy. I've been always thinking like. A car needs driver, therefor it has a canopy. An rc car doesn't need it as the driver is remote. Does it really need to look like a car.

My first 3D print project. Way to heavy

Second

Too much petg makes it weak though:

Current mash-up of the Hobao

No canopy reduces the frontal surface area /drag coefficient. It works, you can tell from the reduced ampdraw. (even due to increased weight)
the reduced downforce does require a smarter floor, diffuser and spoiler to compensate.

 

[The Donut Man]

I thought I knew how big this thing was going to be...

WOW am I excited! And Castle was nice enough to include 8AWG motor wires and male bullets

 

[Hammer Down]

I thought I knew how big this thing was going to be...

WOW am I excited! And Castle was nice enough to include 8AWG motor wires and male bullets
View attachment 135657

They are rather large aren’t they way bigger than the MMX8s.
This reminds me, I need to check the box on my second one, I ordered more 8awg and bullets assuming I needed more.

 

[LibertyMKiii]

I've followed your work on the carbon bodies, awesome work!

This baffled me 20 years ago. Having been told this as a kid, I built an RC plane with a symmetrical airfoil and found myself questioning this explanation. How did it fly when the profile at the top of the wing was identical to the bottom? This got me wondering how a plane with a conventional airfoil flies upside down. Then I started questioning how Bernoulli's principle could account for producing the amount of lift an airplane needs. For reference, the new 777-300ER max take off weight is 774,600 pounds!

I was curious, so I read a lot about this and even used this as a topic for a research paper in '02. What I found is that deflection is actually the primary source of lift. Angle of attack is critical to deflecting air and airfoils are designed to do it in a an efficient and stabile way, the relatively small pressure differential created by Bernoulli's principle is a welcome byproduct. I share this respectfully, and for nothing more than the sake of exchanging information.

https://www.grc.nasa.gov/WWW//K-12/Summer_Training/Elementary97/planearticle.html#:~:text=Air.,pulling the surrounding air downward.&text=An airplane wing is shaped,the wing deflect the air.

https://www.sciencelearn.org.nz/resources/300-wings-and-lift#:~:text=According to Bernoulli's principle, the,air become more spread out.

Most of the good hard data you can find on aerodynamics pertains to airfoils and flight.
Data on airfoils near the ground or automotive purposes of ground effect tend to be trade secret by auto racing teams.

Ground effect and automotive aerodynamics is a tricky thing, luckily CFD has come along way in recent years, which helps. I am always happy to discuss via PM if you want to discuss further. I don't wan to clog up the OPs thread too much about our discussions/taking away from his build discussion.

 

[The Donut Man]

ESC soldering is done. I made the motor leads short with a little bit of leeway; I like ‘em tidy. For the battery I’ll be making a harness that allows 1) the cap pack to be removed and 2) eventual modification for 8S running next summer. I’ll be using a female QS8 connector on the ESC side which has a recessed negative bullet, hence the offset heat shrink. Connectors should arrive later today (I got blue ones and wanted black ones because I’m picky) so I’ve got some more work ahead of me.

 

[The Donut Man]

ESC is wired in! No idea where I’m going to put Perfect Pass though I’m quite happy with the length and how tidy everything turned out with the swap. Does anyone use a massive receiver box that could hold, say, two receivers? That would be awesome.

 

[Doom!]

That does look clean!

 

[rotauq]

Very good job!
Now I remember why i switched to a GT body, it gives so much more room in the car.

 

[The Donut Man]

Very good job!
Now I remember why i switched to a GT body, it gives so much more room in the car.

Yes it certainly does. Most of my stuff is inside the chassis edges, though! When I switch to 8S next summer, I'll be making my entire layout sit very low so that I can experiment with canopy-less bodies My goal is to make a full aluminum under-tray that doubles as extra mounting area, probably starting in May.

 

[rotauq]

Somehow my Jaguar body lost it's canopy yesterday

 

[The Donut Man]

Went to set up Perfect Pass, and my initial data log showed an unusually low voltage from my Panther 6S. Long story short, one of the cells died so I had to get a new one. Interestingly enough, the new battery's thickness is decidedly reduced. I'm almost certain the old battery didn't puff, because nothing in the shrink wrap is stretched and all the faces are pretty flat. Guess I'll find out soon if performance is any different!

 

[rotauq]

Went to set up Perfect Pass, and my initial data log showed an unusually low voltage from my Panther 6S. Long story short, one of the cells died so I had to get a new one. Interestingly enough, the new battery's thickness is decidedly reduced. I'm almost certain the old battery didn't puff, because nothing in the shrink wrap is stretched and all the faces are pretty flat. Guess I'll find out soon if performance is any different!

View attachment 141936

I would almost say it's a 4S. But i know they are even flatter. Interesting

 

[jondilly1974]

Went to set up Perfect Pass, and my initial data log showed an unusually low voltage from my Panther 6S. Long story short, one of the cells died so I had to get a new one. Interestingly enough, the new battery's thickness is decidedly reduced. I'm almost certain the old battery didn't puff, because nothing in the shrink wrap is stretched and all the faces are pretty flat. Guess I'll find out soon if performance is any different!

View attachment 141936

Wonder if it’s a mismarked 5.0?

 

[The Donut Man]

Wonder if it’s a mismarked 5.0?

I didn't think of that; I'll doublecheck the dimensions with those on the website. Funny thing is, the 5.0 has different height and width dimensions, and the only difference between these is the height.