Random video blogging

Modern manufacturing technologies enable strange shapes and could produce unconventional pumps. What is good for small scale rockets if turbines and centrifugal pumps have too much tip losses?

Rotary engines have vastly better power to weight ratios and vibrate less than piston engines. They’re also expensive and hard to build (cue modern manufacturing again). Here is one demonstrated in a paramotor, Parajet Cyclone using a Rotron engine. Love the music.

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Helo Speed Records

This is becoming an aerospace video blog. 🙂

The eighties

Versus the teens

Westland Lynx only reached 90 m/s while X2 is doing 130 m/s. The ability to let the rotor spin slowly since only the advancing blade needs to lift in a counter rotating rotor allows the X2 reach a high speed.

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Sankrithi Channels Wallis

Most people with interest in aerospace history know of Barnes Wallis’ geodetic structures, most famously used on the Vickers Wellington. He first invented them for the R100 airship, basically a weave of thin aluminum shapes going in different directions, forming a grid. No bulkheads or even wing spars needed, but it was quite complicated to build. Fabric was used as a cover, first linen and later thin steel wire mesh. It became outdated when airplanes were pressurized and moved to aluminium monocoque structures.

Well, now, airplane manufacturing technologies are changing again, after some 70 years of riveted aluminium sheets, bulkheads and spars. Composites laid by robots enable fancy shapes, and optimizing the strenght carefully in various directions. Boeing has been looking at a 737 replacement. So far, pressure hulls have had to be cylinder or ball sections – only that way the thin skin can be in pure tension, the only force it can really resist. Often a double bubble has been used, with the cabin floor dividing the lower and upper half into two circular sections and also keeping the left and right side together at the same time. A circular frame is not very space efficient for humans though, so Sankrithi et al at Boeing figured out how to put fibers in a grid to enable a roughly elliptical shape that is wider than it is tall. The advantages are not entirely clear to me from their description, since they seem to say the ratio of seats per circumference is similar to a circular frame, but it is nevertheless interesting. (Also, it’s strange that Free patents online shows that the patent was filed in 2009, yet Google shows it was filed in 2005, yet they seem the same at first glance).

This has some relation to the X-33 where they also attempted non-cylindrical composite pressure vessels. The technology has advanced since though.

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The Turn-Boost-Glide-Back approach for first stages

In a patent by the famous Barnaby Wainfan. EDIT: corrected the link. This patent was filed in 2006 and granted in 2008.

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The Swiss Monotracer Two-Wheel Car

If you speak german, this video is nice. They show it driving, in construction and design.

Though it is complex, heavy at 450 kg and expensive at 62,000 euros. Uses a BMW motorcycle engine and sits two people in tandem and looks like an airplane cockpit. It could serve as an interesting datapoint if more fuel efficient non-mass transport vehicles are to be developed for single commuters. The E-tracer version has had success in the automotive X-Prize. It’s no small deal, since that includes handling tests.

Overview of the Monotracer in english:

Lane change handling test at automotive X-Prize:

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I’ve Returned



Too much to fit into one update. The leads could be

Communisms’ legacy

• in the Baltic states
• in East Berlin
• in demographies
• its relation to other genocides like the holocaust
• a prison
• how do the people live today
• Ignalina and its replacement

• (Peripherally a subject matter, the western powers’ somewhat interesting views on Finnish-Soviet wars and relations and their potential wagings of war against the reds – project Pike forum summary and the book here)

Russian forest fires

• Beriev’s share price (A Be-200 appears on the video 15 seconds in, hat tip to Secret Projects)
• organization of society and its ability to handle crises
• the smoke in Helsinki because of that
• should they care

Hot weather

• Here, after the coldest ever winter comes the hottest ever summer
• Is it largely just winds from the southeast’s continental hotness – when usually they blow from the more marine southwest?

Climategate blahblah

• BBC has apologized and some NYT reporter has said the NYT should apologize on some small back page article.
• Follow Michael Tobis for climate related news

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Lennusadam – Tallinn’s Seaplane Hangars

I didn’t have a camera with me but I was surprised at their impressiveness. From afar, they looked like old gas storage vessels (like in Suvilahti, Helsinki), but they really were dome-shaped seaplane hangars. Luckily Flickr has at least some photo as well as Panoramio here. The museum has home pages here.

I picked the wrong day to go there as it seems all of Tallinn’s museums are closed on mondays and tuesdays (The Kumu art museum was one potential destination too), but I couldn’t really choose the day anyway at that point. I could still tour the stuff that was outside. There was a lot of construction and renovation work going on. The domes were full of scaffolding for builders. Actually that would have provided for a really good photo opportunity since it divided the volume into cubes as a great visualization of the size of the thing, together with people for scale. The top was being sandblasted and you could see the rebar from many places. This is not a cheap project and will be ready by 2011.

They are not super-huge though. No Saro Princess could fit in them. They were built in 1916 and 1917 after all! I could also see the old first independence battle’s ice breaker Suur Tõll and the Lembit submarine, as well as an array of patrol boats donated by various countries to the young Estonian defence force in the nineties.

I will write other things inspired by the trip in other posts, there was certainly a large amount of thoughts that arose and observations that were made.

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Sukhoi T-50 Video

Showing closeups of the new Russian stealth fighter on the ground, testing thrust vectoring, showing the drooping forward wing gloves, and then in flight. It’s a treat!

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Plotting and Printing Airfoils in Matlab

Gah, got tired of monkeying around with various software (XFLR5 is never provided as an executable on ANY platform despite countless requests, just some packets) so loaded up a profile in Matlab and plotted it in multiple sizes and printed those. Took only a few minutes. It’s still the best software ever.

It went something like this:

load MH78.txt %text file is copy-pasted from MH-aerotools.de
whos %check out if it worked
MH78 %check out what we just loaded

figure
plot(MH78(:,1)/100,MH78(:,2)/100)
grid
axis equal
legend MH78

%perhaps print here if it fits on one paper

%this is three views for a larger print:
xlim([0 0.4])
%print here manually
xlim([0.3 0.7])
%print
xlim([0.6 1])
%print

%Etc you get the idea...

Had to read some documentations for this, but the gist is that Matlab actually has some proper documentation. I just typed help gca, help set, help axis, help axes, help xlim etc and they contained some quick examples that I then tried and got the hang of everything. Matlab should be the gold standard for all similar software developers. I’ve tried coding in Python and Scilab and both have large stumbling blocks in quick and efficient numeric work.

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The US Air Force Tries To Do Reusables

But is not a real RLV program. It’s just a narrow test for one technology. Hence I think naming it Reusable Booster System Pathfinder is misleading.

Overspecification

They overspecify the problem by requiring a glide landing. Why is it superior to powered landing? At the moment, there’s no clear reason to believe it is! Both need to be developed further to understand their advantages and drawbacks. To my knowledge, there have been only six liquid rocket VTVL prototype manufacturers so far: McDonnell Douglas, JAXA (who was the contractor?), Armadillo Aerospace, Blue Origin, Masten Space Systems and Unreasonable Rocket. Only a few of those have flown to higher than a few hundred meters. The design and operations space is mostly totally unexplored.

Nevermind the large number of other alternatives to boostback. Jon Goff had a recent “lecture series” about these.

I understand that this is just one program, but this should not gain the status of the reusables approach of the air force – stuff like that easily happens.

Master Design Fallacy

They also discard evolution and competition – instead just requiring a single masterfully designed prototype before something operational. Sure, this is much better than starting a multi-billion dollar program without a first lower cost prototype, but nevertheless, it sucks. Somebody brief them on newspace! Rand Simberg, Monte Davis, Jonathan Goff, Clark Lindsey, or one of the numerous people who get it. Or one of the prominent company leaders: John Carmack, Jeff Greason, David Masten.

An Ideal Program

Just specify some boost delta vee points and let companies demonstrate progress towards that. A popup tailflame lander would perhaps give more vertical velocity while some good glider or even a booster that has engines for cruising back could boost far down range to give lots of horizontal velocity. There ain’t a clear winner – there might not even be and multiple approaches would have their uses.

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