A gas powered quadcopter capable of autonomously picking up and delivering a payload of 50 pounds. Read more
This project was successfully funded on February 25, 2013.
End of Semester Update
The semester is over, we have all graduated, and an update to our generous backers is well over due! I do apologize for not getting something together sooner. The last couple of months have been particularly hectic, and all our efforts have been focused on manufacturing HLQ. Now that school is over we have the time to make the detailed update that you all deserve.
Before getting into the details, however, I'll give you the quick version:
- Nearly all engineering tasks are completed including design and analysis tasks.
- All major components and most minor components have been purchased and/or fabricated.
- A test assembly to 75% has been completed and all parts fit as expected (so far)
- Flights tests were scheduled for the week before finals. However, an outside manufacturer failed to make parts to specification making flight impossible for now.
- Final assembly and flight testing is now scheduled for later this summer (By August 21st.)
We have been extremely fortunate in that, besides the generous funding, we made numerous contacts through Kickstarter which has culminated to make HLQ a possibility. One major example is that the General Manager from TechShop San Jose contacted us with an offer for sponsorship at the shop. He gave us all memberships and several free classes so that we could make the rapid prototyping of HLQ largely a success. In the course of basically 2 months, we were able to purchase materials/parts and fabricate almost all of our over 600 individual components!
Another contact was made with Schnell Aerospace. They generously offered to provide a very detailed theory based elemental analysis on our blades. Their results very closely correlated with our testing. Our testing, however, only went up to about 2,200 RPM out of the ~3,000 that our blades are rated for. Because of Schnell's help, we were able to determine that the blades are capable of (at least in theory) a total of about 180 pounds of lift!
That is good news, because it turns out that our frame design has come in a bit overweight. We originally planned for 50 pounds of airframe, and 50 pounds of payload. But, our design came in closer to about 62 pounds (not including fuel). We have high hopes that the additional lift the theory predicts will make up for the overweight frame.
We also experienced some major difficulties through the last few months. We spent countless hours in the shop, often from 9 am to midnight away from our families and friends. We also had to cope with the completely unexpected passing of Craig Stauffer who was the San Jose State Engineering Department shop tech in charge of manufacturing a large number of parts for all the senior engineering teams at San Jose State. Not only was he a talented machinist, he truly held the student's best interests in mind. He was a good friend to the team and to the project, and will be missed dearly.
As far as completing the project is concerned, however, the most detrimental challenge we faced (and are still dealing with) is also the cause of our delay in flight testing. HLQ is driven primarily by high power, high torque belts. These belts were selected based on the high RPM, Power and cyclical torque loadings that are expected to be transmitted through them. While the belts are off the shelf components, custom pulleys had to be designed and manufactured to address the issue of weight. Only steel pulleys are available commercially which would have been prohibitive when considering weight restriction.
So, we designed the pulley and sent them out to a company that specializes in gear and pulley manufacturing. With complete specifications and tooth profile information, the pulleys were made and received. Upon inspection, we quickly realized that the pulleys were made to the wrong tooth profile. Contacting the manufacturer, we found that they could not make the profiles that we called out in our drawings. We contemplated running the belts anyways, but quickly decided against it because we were all certain that the belts would likely fail almost immediately.
So, that bring us to where we are now. We are currently considering what direction to take in manufacturing these pulleys ourselves. We have several options (CNC them, design and make a tooth profile cutters, etc) and we are now in the process of determining the best route to take.
As for all the rewards we owe our backers, don't worry. Because of our TechShop sponsorship, we have enough money to still fulfill all our rewards AND work through the pulley issue, even though we will be buying all new raw material for manufacturing. The rewards, will, however, likely be slightly delayed so that we can still work on getting HLQ airborne and accomplishing it's specified tasks. Once that is complete, t-shirt design surveys will be sent out, reports will be printed and bound, and all focus will be on getting to you, our backers, what we owe you.
Lastly, we have been sending semi-regular updates through the Incredible HLQ Facebook Page, so if you haven't already liked us there, please head on over so you can get pictures and short updates on our progress. Also, I realize there are no photos in this post and many of you probably want to see what we've been doing. We do have lots of pictures to show off, so I will be creating a image gallery on the Incredible HLQ Website.
And that's all I have for today. We will continue working on HLQ through the next couple of months, although at a somewhat slow, more sustainable pace. The next time you hear from me, I hope it is with a video of our first successful test flight, and with information for our bakers who will be attending the viewing party on dates and location possibilities.
Thanks again for all the support you have shown us!