XLR-1

XLR-1

This project includes development of the next generation of frames that began as a speed project, but will also give rise to production frames for racing, freestyle, and endurance.

Contents:

  1. Progress Updates
  2. Frame Evolution… or Revolution?
  3. Lightweight Frame Test
  4. Modular Design
  5. Electronics

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Progress Updates

December 8, 2017: The Future is Clearer: Not so clear on the site – I will have to expand on this over the next few days (slightly). In short, the speed fleet is being built. They are slightly different from each other and completely interchangeable with one another using a modular design. If a new idea does pop up, it can easily and quickly be integrated. Overall I am extremely happy with just about all aspects of the design, but I am extremely unhappy with the weather. Hmmmm, maybe a heated transmitter powered by a lipo should be next on the project list…

November 28, 2017: The 5″ production prototype (race/freestyle) is a bit heavier than anticipated at 44g, but it should be able to be trimmed to 36-38g. More info is in the video description about the build, but it was done in an extreme rush. Some specs so far:

  • 215mm Motor to motor distance
  • Final design will be around 36-38g
  • The only fasteners will be for the motors and the stack – no fasteners, epoxy, glue, etc. is needed to hold the frame together (although the one in the video used 2)

November 14, 2017: The next prototype frame is well under way. I do not expect much to happen in terms of flying, but if I do get a chance, it won’t be a surprise if it breaks 165.80 mph mark set by the VXR-190. Although I expect this prototype to do very well, there will be more frames being built to hone in on the features that the final build will have.

November 5, 2017: I finally had a flight with the first frame design which is already obsolete, but it still had some other aspects that had to be tested and was successful. I’m not bothering with video since it was beyond boring and I was only flying with a 4s. So now it is on to the next frame. If it goes the way I hope, it is going to be very cool in terms of having a modular design.

By the way, with the updated Blheli 32.1 update, the Wraith32 ESCs sound great.

October 5, 2017: I never quite finished the first prototype (this is common for me), it never quite felt right. The 2nd prototype frame is almost done (no electronics yet). The arm design is radically different from previous designs. Once this design has been proven, it will be on to the more refined version. However, both of these frames (if they work) will not have the goal of all out speed. As stated earlier, the current goal is to get some testing on different configurations – many different configurations that can be accommodated and switched out (relatively easily) on the test frame. Whether it hits 200 mph or 36.2 mph, I will be sure to post videos. Hopefully this will be next week.

September 2, 2017: After looking at this build, I really don’t expect to be finished until spring. Although this sounds like a long time frame, a lot of progress will be made along the way. Why? This design is more of an adaptive design (at least that is what I am aiming for). There will be a core frame which can be modified relatively quickly with different sub assemblies. With that being said, there might be many configurations that will be tried out before the best combination is found.

August 29, 2017: The official start of the next speed project. I don’t have any specific goals or speeds to hit since there are a lot of unknowns. It really kills me, but for good reasons, I will be giving even less details about this build for the time being.

I do plan on posting what I can (numbers, logs, video, etc.) as things progress. I hope to have a frame or two built by this weekend, but as history has shown, it will probably be 2 or 3 weeks until something good happens.

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Frame Evolution… or Revolution?

Although flying time has been lacking, there has been plenty of time to develop, evolve, and build different arm configurations using different construction methods and materials. The latest configuration design is extremely promising as far as versatility, strength, low cross section, balance, and has a high possibility for production kits. The design scales down extremely well while retaining its strength.

Another big development is the motor mounting. It might sound odd, but it is a big breakthrough.

So far, these are the frames that have been constructed using this method and their weights. Just in case, a lot of this should still be taken with a grain of salt and all weights given are bare bones:

  • 5″ Speed Drone Frame: 26g (excludes nose and tail cones)
  • 5″ Freestyle/Race Frame: 20.25g. This frame has me very, very excited.
    • I would like to refine this version into a frame that can have replaceable arms. I am guessing it would add another 6-8g.
    • There is a slightly promising method that might only add 2-4g to have the arms replaceable.
  • 5″ Light Weight Frame: 9.96g. Although this frame can support 95 lbs (see picture below) this might need just a little more to strengthen it (torsionally), but It shouldn’t be more than 11g.
  • 5″ Featherweight Frame: 5g or less. This is still in progress and is at 4.45g. I am still pinching myself over this one… but something tells me it wouldn’t hold up to hard flying. This one is on the shelf for the moment.

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Lightweight Frame Test

A dirty test setup: the frame is placed over a pot. The arms are supported on the rim near the motors. In the middle of the frame is a 1.5 inch square block to set weights on. I ran out of weights, so I threw the bar on too.

DSCF8319
I ran out of weights, so I added the bar. It might look like some weight is resting on the pot handle, but all 95 lbs (roughly) is resting on the 5″ 9.96g frame which is hidden under the weights.

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Modular Design

Just a quick mention – I can see this frame being developed into a kit that can be configured several different ways by adding components to the bare bones frame.

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Electronics

About the only thing I have confirmed is using a Betaflight F4 flight controller.

Betaflight F4 front

Betaflight F4 back

For the initial ESC choice, I will be going with the Airbot Wraith32 Metal. Since Airbot was nice enough to send these to me, this might be a good chance to redo my Wraith32 review. Apparently, the firmware was at fault on my initial review.

The reason I want to use these ESCs is so I can record and analyze the data from the ESC telemetry.

Wraith32 Metal
Wraith32 35A on the left and Wraith32 Metal 65A on the right

And of course, I will be using the ublox M8N for the GPS reciever.

t150-04

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6 thoughts on “XLR-1

  1. Torashuu says:

    Very nice site, was wondering when someone was actually going to design around frame aerodynamics in a more rigorous way. I’ll be keeping an eye out for any frames you might put out.

    Liked by 1 person

    1. downanddirtydrones says:

      Thanks! Truthfully, the site is a little disorganized. I need to take a day or 2 to clean it up. Aerodynamics on these things are not straightforward – I think there will always be a compromise but I’ll try my best.

      Like

  2. Torashuu says:

    Dont worry about site organization, so long as the principal ideas are there (excempting those involved in any patents of course). Just the clarification of the possible gains, the back of the envelope calculation on maximum attainable speed already sets some rough limits and goals that give you something to work with, contrary to regular frame design which seems mostly based on gut feeling and user feedback. Not to mention this actually gets me thinking about custom frame design for myself. 🙂

    Liked by 1 person

    1. downanddirtydrones says:

      Glad to hear – back of the envelope is about all you can do with these things. It was a good sign that I was doing something right when a small group of guys took me in back in July – very smart guys. A few affiliated with R & D in various aerospace and air defense industries, dozens of patents among them, all retired early – hopefully by their choice 😉 We have a rather lengthy confidentiality agreement among us and we bounce ideas, verify, etc. Since being in the group, I haven’t had to change the Speed Calculation spreadsheet at all. That’s not to say it couldn’t be improved! Although the website is in the doldrums (as far as info goes), things are busy behind the scenes – very tough to stay focused… I almost forgot to mention: frame design is addicting. I started by modifying existing kits. Some are so cheap, you can buy a few kits and use them for materials.

      Like

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