Airship Velocita Build

[Jarron]

Ever since I saw one as a small child at a baseball game, airships fascinated me. As I grew older, I learned about them through books, their history, how they flew and the physics behind them. I even had a toy R/C blimp which flew pretty poorly, though I had a blast flying it around my living room. Fast forward to 2023 and I had discovered videos of R/C blimp races in Germany such as this:

Soon after, I learned about a new company in Germany called Windreiter: https://www.windreiter-shop.com/shop/
They manufacture R/C airship mylar envelopes in several different sizes, as well as custom designs if needed and recently, they started producing their own airship kit, the Velocita:

Home | Windreiter

Windreiter is an expert in lighter-than-air technology. From fully integrated autonomous inspection systems, to title-winning racing airships, we do it all!

www.windreiter-shop.com

It is described as a fast, sporty airship for hobbyists, student projects and racing. Of course, I had to try my hand at it for myself. The kit straight from them includes everything you need to get going, including a battery, battery charger, receiver and radio. I reached out to them and asked if they could omit this from the kit, which Windreiter did and it put a massive dent in the cost.

A couple weeks later, I received the kit in the form of this box, it all arrived safely:

View attachment 15789
Underneath a bit of packing material was a near cardboard sandwich containing all of the components of the airship. All parts were secured nicely with tape, double stick tape or twist ties with foam blocks under the heavier components to prevent damage, I was quite impressed to say the least. Here's what I got.

• CNC cut 6mm depron keel, fore rudder and aft V tail fins and ruddervators
• Various electronic components, the servos, motor, ESC, servo extension wire as well as CNC cut ply keel reinforcements, hinge points and control horns and a bag with some balloon clips, zip ties, 1mm carbon rod, some 1mm music wire and a GWS 5x3 tri blade prop
• Motor mount, fin mounts and a battery charger, which was donated to a new R/C pilot. Underneath this layer were three mylar envelopes, each folded neatly in their own little bags. They were nice enough to supply a fourth smaller envelope to play with as well.

Let's get started. I used foam save CA and foam cure for the whole build.

After sanding the edges of all wood parts smooth, (sharp edges + airship = bad) I CA'd these two hinge points for the fore rudder in place at the bottom of the keel, then installed the keel bottom side reinforcements. With more foam safe CA.

This is the motor mount assembly, it is made up of a very lightweight yet strong sandwich of 8mm depron and what appears to be 1/64th ply and has lots of mounting holes for different motors.

 

[Jarron]

Of course, I forgot to take a picture of the mount installed on the keel, so here is a picture of that step in the manual.
I used small amounts of Foam-Cure for more working time:

Next comes the fore rudder servo mount, also made from 6mm depron. It tabs right into the upper rear of the keel:

The kit came with this little black 3D printed adapter that glues onto the fore rudder steering servo, let's just dry fit it and--hey! The hinge slots don't line up! Time to get the razor knife (Note the little dots, I had already measured how much I needed to take off.

All good! A 1mm carbon fiber rod goes up through the hinge points and alll the way to the servo arm through that recessed channel in the fore rudder to tie the assembly together.

On to the rear end. The fins and ruddervators are made from CNC cut 6mm depron and get cut out of their frames.

More of those little hinge points get glued into the slots in the fin trailing edge, then it gets pushed into the slots in the ruddervator More 1mm carbon rod ties it together and a control horn is glued in place. This all repeats for the other fin assembly:

The linkages are simple 1mm music wire with Z bends on each end:

 

[Konrad]

WOW, I'm glad to see more detailed builds. I'm loving this and threads like @Mucksmear 's E-Hawk ARF builds.

 

[Jarron]

Here is what the completed assembly looks like. This will go on the BOTTOM of the airship. more of that ply/depron sandwitch is used:

The Hacker A10-15s motor gets mounted. Time to test fit the keel and tail assemblies on the envelope:

Not wanting to waste my precious Helium reserves, I inflated the envelope with air to check for leaks, after a couple days, I found there were none.

This thing's getting pretty big, I can't even fit it all in frame. The keel and tail assembly are mounted approximately where they should be with plain old packing tape:

Two 77 inch, 32AWG extension leads were provided for the tail servos. I crimped on female plugs on one end, males on the other.
I didn't need all of this length either, so the excess was cut off. The extensions got routed along the belly of the airship:

 

[Jarron]

Electronics layout. The battery will go towards the bow of the ship. I got rid of that blue zip tie shortly after this picture was taken and just jammed that wiring between the keel and the envelope to keep it out of the prop:

The complete ship minus Helium..let's take care of that. Just gotta rip the keel and fins off, keeping the servo extension leads attached to the envelope and suck out all the air. I made sure to mark where the assemblies need to go once I get it filled again

Several cubic feet of Helium later..

And there she is, the racing airship Velocita! The total mass was about 200g, not much to get moving. She's moored to a rack with the included mooring carabiner which gets taped to the bow.

 

[Red]

Man I hope there is flight video.

 

[Konrad]

As this is always “flying “ how are you planning to moor her at the field? As I recall this is a bit of a problem with the full size airships.

 

[Jarron]

These airships are mostly used indoors in large gymnasiums, exhibition halls, etc but that I took the Velocita out to my local flying field for her first flights, as the weather forecast said zero wind from 4:00 AM till around 12:00 PM. It was overcast and not too warm out, meaning there wouldn't be much expansion of the Helium causing issues with the ballast, though I still ballasted the Velocita slightly heavy just in case. It was not long before my unsuspecting clubmates pulled in to see well.....this.

After final control checks, the Velocita was ready for her first flight. I unmoored the airship and took it to the line, then announced "UP SHIP" as I nudged the ship into the air, then throttled up and away. To everyone's surprise, the Velocita proved to be just what it was meant to be, a sports model of the airship world. She'll cruise along leisurely at low throttle settings, yet zoom along at if you want, though you have to keep your hands on the sticks to keep her straight. The Velocita makes nice, flat and sharp turns, thanks to that fore rudder that shoves the nose around quick and counteracts the roll moment imparted by the ruddervators, though like on a large boat, things do take some time to happen due to the sheer size of the airship, especially at slower speeds. Just for fun, I tried to loop it, which resulted in the ship performing a sort of Immelmann turn.

Here's a flight video my friend took. He cut it before I would've liked, though it shows the airship flying nicely:

All in all, the Velocita was a pleasure to build and rewarding to fly from sourcing Helium to figuring out how to cram it into my car. It would make a great first entry into the world of R/C lighter than air and a VERY unique addition to your hangar.

 

[Konrad]

That's cool as hell!!!

 

[Hank GB Z]

Agreed. That is cool as hell. Good job Jaron. I know you’ve been trying to build a LTA air ship for some time.

Hank

 

[Wayne]

I keep bugging him to fill it with hydrogen as the Helium is not cheap these days. Jarron tells me the manufacturer is working on doing just that. Make your own hydrogen at home for cheap and not worry to much about loosing some or needing to drain and refill with fresh helium.

 

[jure]

Hydrogen brings memories of the Hindenburg , please be careful!

 

[Konrad]

As I’m sure you know the main issue with that ship was that it was painted in rocket fuel (aluminum nitrate) to protect the skin from ultraviolet light. Reports are that the fire started at the rear right (away from the cameras) as soon as the mooring lines hit the ground (static discharge). You can see the flame propagation from the rear forward along the equatorial (middle) longitudinal line. It took a long time before the hydrogen gas bags actually failed allowing the hydrogen to mix with the air and burn. In many environments gasoline is thought to be more hazardous than the unpressurized hydrogen.

P.S.
Read the RAF reports on the difficulties of getting the zeppelin to burn In WW1. Even with incendiary rounds of the time they wouldn’t burn. It would take a special round and tactics to get them to reliably burn.

 

[Konrad]

The Idea of racing blimps looks like an oxymoron to me. At speed I’m wondering if these tear dropped fuselage showed any of the stability issues the USN was addressing with the USS Albacore (the first modern shaped USN submarine hull). It was prone to cork screwing to the deep when turning at high speed. I saw some of this in those videos.

 

[Jarron]

The Idea of racing blimps looks like an oxymoron to me. At speed I’m wondering if these tear dropped fuselage showed any of the stability issues the USN was addressing with the USS Albacore (the first modern shaped USN submarine hull). It was prone to cork screwing to the deep when turning at high speed. I saw some of this in those videos.

oh! that's the "Oh Jesus Christ" effect I learned about in the racing blimp community, I think it has something to do with motor torque and the conventional rudders making the ship roll onto its side in hard turns. Now your rudders are elevators and they're shoving your nose into the ground! The fore rudder thingy on the Velocita prevents this.

 

[Mucksmear]

There was an interesting docu on the Hindenburg - something about the chief fabric guy being away during construction, so the fabric was applied without the benefit of his particular expertise resulting in loose sections that would flutter at flight speeds which in turn caused internal bracing wires to slacken to the point where the gas bags were getting seriously chafed. There’s a theory that a bag may have been chafed compromised and leaking hydrogen into the space between the bags and the outer skin

 

[Hawaii Sloper]

My grandparents, uncle and mother lived just down the road from the site where this happened. apparently my grandparents saw the ship coming in before the explosion. I was born about 5 miles from there in Lakewood. My grandfather worked as an engineer for the Toms River Chemical Company. Not proud of being from New Jersey though, just sayin. lol

 

[Konrad]

oh! that's the "Oh Jesus Christ" effect I learned about in the racing blimp community, I think it has something to do with motor torque and the conventional rudders making the ship roll onto its side in hard turns. Now your rudders are elevators and they're shoving your nose into the ground! The fore rudder thingy on the Velocita prevents this.

Mass coupling? That is the under slung weight wants to keep going the way is has been going and the aerodynamic controls are directing the gas bag another direction the result is a strong roll The faster the ship the stronger the roll.

The tear drop shape has no keel for the rudder or elevator to work against.

I haven’t read up on the Albacore problems and solutions. I just know there were a lot of stability issues with the tear drop hull.

 

[Wayne]

you can see similar issues with very short wing span lifting body aircraft. Lots of stability issues in roll axis. Watching the college aero challenges where they have a class that uses very short span models to lift soccer balls. For sure these models have all had "interesting" handling qualities.

There was a "blimp" shaped heavier than air model from 1954 called the Martian Spaceship. It had the same sort of roll axis issues. A long but short vertical across the top helped reduce the oscillations.

Personally I think scale like speed would be what I would focus on rather than racing around. Then no real issue.

Got to say that blimp control does work well, it's like front wheel drive for your blimp. Well thought out and seems to do the trick well.

 

[Konrad]

Loved the look of the Martian Spaceship. That little vertical fin at the front added the stability similar at dihedral