[burpg] We Build Hybrids... JK LOL!

From: Joseph Beaupre <joebeau@xxxxxx>
To: burpg@xxxxxxxxxxxxx
Date: Wed, 19 Aug 2015 23:11:08 -0400

Hey Everyone,

There was talk about going liquid at the end of last year, and it may
actually be happening. This is for two reasons:
1) Hybrids are expensive
2) Our skills and support is shifting towards liquid development

Now, let me explain:

1) To get the Mk. V to the test stand again will cost about $35,000. To
stay on schedule to launch, we have to have the first test by mid to late
October. BU has also enacted a new policy where we cannot borrow as much
money from the college of engineering against money we think we can raise
through future sponsorship- we did this a lot last year, assuming we would
have ULA, Aerojet Rocketdyne, and Dassault sponsoring us by the end of the
year. None of them came through, and we ended up with a $30,000 deficit.
This deficit has been worked out with the college, but has left us with a
borrowing limit of $7,000.

Now we would have to raise nearly all the funds for the MK. V test by the
end of September- something historically difficult as actual cash flow from
our sponsors starts around late September and into October. Long story
short, we would not be able to test the Mk. V on time due to its high up
front costs and new spending limits, knocking us off schedule.

The liquid, on the other hand, has costs that accumulate gradually and
mimic our cash flow very well- making it achievable with our new
restrictions. Below is a graph of cumulative costs versus time for both
projects. You can see what I mean:

[image: Inline image 2]

2) While hybrids are more historically 'our thing', the unfortunate part is
that they are 'our thing' because no one else really bothers with them.
Going liquid means that we can get more support to help the project. For
example, literature for liquid engines is much more readily available and
complete. Also, greater industry support means we have more mentors to tap
for knowledge. Armor has volunteered to mentor us, and we also have members
of Aerojet Rocketdyne willing to provide help. We also have members of the
team who have done liquid propulsion at their internships this summer. So
yes, it is new to the team as a whole, but there will be less figuring it
out ourselves than we had to do with the hybrid engine, and the design will
be more intuitive to those members of the group with propulsion
backgrounds.

So where does that leave Starscraper? Starscraper will still launch on
time- Summer 2016. The hybrid combustion chamber will be removed, and
replaced by a fuel tank. The whole system will be pressure fed to a cluster
of 4 engines. The engines are relatively small to reduce manufacturing and
testing costs and speed up development. While the rocket is still called
Starscraper (as of now- we are kinda assuming the engines will be an
S-class equivalent with their thrust and burn duration we would use) the
engine has to have a new name; it's not part of the 'Mk.' series of
hybrids. So, this is an invitation to start thinking about names....

And what about the Mk. VI? Well, I'm sorry, but the Mk. VI might go the way
of the dodo to push funds towards the liquid rocket. -sad face-

There will be more information and specifics forthcoming on the juicy
technical details.

See everyone soon!

--
Joseph M. Beaupre
Boston University
Director, Rocket Propulsion Group
Electrical Engineering 2017

Follow-Ups:
- [burpg] Re: We Build Hybrids... JK LOL!
  - From: Jeremy Pedro

[burpg] We Build Hybrids... JK LOL!

Other related posts: