My attempts at a working Boost Glider

[Dientus]

Thanks to @Hotel26and his boost glider idea, as well as @swjr-swisand his additional design ideas, I decided to create my own Science Boost Glider for use on atmospheric worlds. The savings on fuel would be great and makes sense to me. I will use a standard launch vehicle to get a return pod and a boost glider to a planet with atmosphere and collect (nearly) all science that I can in what is essentially a single mission! Using the boost glider means it can easily be the same tonnage as my usual landers however the bonus is, with its ability to 'skip-hop' across the planet, I can use the same fuel and vehicle to get science from each biome in a single shot and return in the same mission instead of sending multiple missions or large refueling facilities.

 

My first attempt was the XP-87 Harpy (7.603 tonnes empty; 13.723 tonnes fueled)

 

I used a MK2 service bay, crammed all the science I could in it, and tested it. It flew pretty good and needed only a very short runway to get airborne. Quick shot of the service bay.

The problem was it kept hitting an altitude ceiling that was essentially too low for my purposes. Switching modes it still could not effectively leave the atmosphere and skim in with any fuel left. It also had an over heating problem in the RAPIER because of how hard I pushed it while it was still in the atmosphere. I didn't want to add radiators or precooler at this stage since it really wasn't performing as I would like.

 

 

So... the design was nice, but the changes would switch COM and airlift enough to require a redesign... I just started over and used twin intake and engine from a failed (for my purposes) SSTO design (XP-62) and meshed it with the science, basic wing design from the XP-87 to create a completely new Boost Glider...

 

XP-88 Peryton (10.840 tonnes Empty; 18.940 tonnes Fueled)

It may be larger, but the result was great! Exactly what I was looking for!

Of course there was some heating on reentry that could be worrisome, but this is it! It is actually more maneuverable than the Harpy due to better lift to COM placement and COM movement during fuel drain. I am now going to finish up the design, put on the lights, RCS, struts and this bad boy will be commissioned the KBG-001 PERYTON in time for Vals return from Mun.

Many thanx to the guys with the good ideas (Hotel26 and swjr-swis) and to the kerbals brave enough to test these theories out!

Edited April 10, 2021 by Dientus
Went back and added tonnage for Peryton

[Hotel26]

8 hours ago, Dientus said:

use a standard launch vehicle

Very neat way to solve the "getting to space" angle.

Well done and congratulations on hitting your objectives!

[swjr-swis]

9 hours ago, Dientus said:

I am now going to finish up the design, put on the lights, RCS, struts and this bad boy will be commissioned the KBG-001 PERYTON in time for Vals return from Mun.

Laythe may work nicely, having very similar atmosphere to Kerbin, but Duna (too rare) or Eve (too dense) could be problematic.

To have any chance at working on Duna, and for better fuel efficiency on Kerbin/Laythe, giving those wings a bit of AoI will make a big difference. Eve... I think atmosphere pressure and heating, not to mention sheer size, may preclude this from working.

Either way, always good to witness the design progression of concepts. Keep us informed!

[Dientus]

2 hours ago, swjr-swis said:

Laythe may work nicely, having very similar atmosphere to Kerbin, but Duna (too rare) or Eve (too dense) could be problematic.

To have any chance at working on Duna, and for better fuel efficiency on Kerbin/Laythe, giving those wings a bit of AoI will make a big difference. Eve... I think atmosphere pressure and heating, not to mention sheer size, may preclude this from working.

Either way, always good to witness the design progression of concepts. Keep us informed!

Definitely good points. The front set has a slight angle, but I may fiddle with the entire length in more depth. May require further designs for each planetary body with an atmosphere. I know we can reasonably assume that this will be required for maximum efficiency, but I still would love to try it out in all circumstances regardless... I mean... Kerbals afterall

 

[Hotel26]

This is Starling:

  

Don't think 28,250 is yet quite high enough for thermal stability...  (That's a kinda euphemism in our aerospace industry, as ya know.  Translated: "not ready for passengers".)

It's a kind of triple coffin corner with speed, lift and heat...  One thing I like: it gets there fast and then one punches the speed up on Closed Cycle.  Bingo!

(Capt. Donsted Kerman, Lt. Arhat Kerman, Requiescat In Pace.  "They will be missed".)

Edited April 11, 2021 by Hotel26

[Hotel26]

I'm missing a trick, am I not?  I should be using the coupe Mk2 cockpit, with a leading shock intake, like the rest of the pack.    So be it.

                                                                                

Starling, now a "space glider":

 

Edited April 11, 2021 by Hotel26

[Dientus]

10 hours ago, Hotel26 said:

I'm missing a trick, am I not?  I should be using the coupe Mk2 cockpit, with a leading shock intake, like the rest of the pack.    So be it.

                                                                                

Starling, now a "space glider":

 

Nice! Can make a side trip to Gilly as well

[Dientus]

Ok, so I took my medium to heavy duty Lift Vehicle the Hestia II and mounted a custom orbiter and the Peryton to it.

 

It is a nightmare to fly! It's definitely one of those "Fly straight up and turn left" type of vehicles!

As you can see the modifications to the Hestia II with those larger fins. This is the view from the camera of the Peryton down to see the other two fins added to stabilize this thing better. The scientists decided to rename this lifter the Hestia II-M due to the modifications done.

 

And I realized it will be another year before the launch window opens up for Eve! So I am thinking of remounting the orbiter and boost glider assembly to another launch vehicle in the meantime and aim for Duna first, since that window is coming up sooner. The way this thing flies, it may be good the guys get time to just design an entirely new launch vehicle from the ground up.

 

 

Edited April 12, 2021 by Dientus
grammers

[swjr-swis]

33 minutes ago, Dientus said:

Ok, so I took my medium to heavy duty Lift Vehicle the Hestia II and mounted a custom orbiter and the Peryton to it.

It is a nightmare to fly! It's definitely one of those "Fly straight up and turn left" type of vehicles!

Hmm, it's hard to tell from these angles, but I wonder how you attached the Peryton to the rest.

I hope you're not trying to directly stack attach from the dual RAPIERs. Due to how KSP works, only one of them will be actually attached, leaving the other to bend freely. I could see that causing all kinds of problems during ascent!

Personally, I'd go for a mirrored booster set for the Peryton. it could still be attached primarily from the aft node on the RAPIERs, further strutted to enhance stability . Or just forget about those RAPIER nodes entirely and use hardpoints/pylons - with the additional issue of having to manage off-axis thrust (gimbals!).

Could still work if you want to include the additional orbiter in the same launch, but you'd need to find a different way of attaching that too.

If you're really dead set on mounting it on top of a single booster assembly, I'd strongly suggest using one of the open nodes inside the Peryton cargo bay as the attachment point, then offset down to make it visually be in the right place. It'll still be a bit bendy and need some extra strutting, but at least the one joint will be centered on the thrust axis.

 

[Dientus]

I will take a look at that. When launching it acts top heavy with the lift too far forward the COM. When it flips, it doesn't break apart, I used the same split tank (empty) on the peryton with two seperators, one for each RAPIER. It APPEARS to be solid but its possible the two struts are stabilizing it. I can take a close up pic of the setup if you like, not at the desktop currently tho.

 

I agree 100% on mounting it on top a booster assembley. A shuttle I have has SRB's to get it into space, but just below the Peryton is the (unamed) orbiter. Its pretty big as it carries enough fuel to catch the Peryton on one of its atmospheric skips and refuel it again for Eve dive.

 

Since it was just a modified preexisting lift vehicle, it's no trouble to redesign

[swjr-swis]

27 minutes ago, Dientus said:

I used the same split tank (empty) on the peryton with two seperators, one for each RAPIER. It APPEARS to be solid but its possible the two struts are stabilizing it.

Yep that's the struts at work - one of those two separators isn't actually attached.

 

Grab some random part and zoom inside the split tank. You'll see that one of the nodes is still showing the green 'attach here' orb, indicating an unused node.

It looks pretty solid and neat.

But as far as KSP physics is concerned, it's only attached on one of the sides. On a heavy assembly subjected to lots of drag and thrust, this will be a very asymmetric bendy point, and make the craft very hard to control.

 

Edited April 12, 2021 by swjr-swis

[Dientus]

I noticed this was assembled in the SPH, I assembled mine in the VAB and used radial and not symmetry where a single seperator was doubled. I assume the same thing happens. 

 

I appreciate the assist! I will upload the craft to KerbalX sometime later after work.. real life calls.

 

[Dientus]

No pictures to show yet, but I couldn't wait any longer. Between finishing other space projects and missions, waiting on the proper window, and RL job... I cheated the Peryton into low orbit around Eve just to see how it performed.

 

Mixed results. I mean it was actually a success on the one hand, but using strictly the closed cycle it drained too much fuel and basically was a one shot lander. I could glide in all the way shuttle style, no power, land, take science, then lift off and fly to orbit, but by the time it exited the atmosphere, no fuel. I wasn't planning on refueling on EVERY landing.

 

So ... Technically success in that it can do the original job, but a failure as a boost glider since it needs constant refueling.

Edited April 15, 2021 by Dientus
strike out incorrect statement

[swjr-swis]

6 minutes ago, Dientus said:

I could glide in all the way shuttle style, no power, land, take science, then lift off and fly to orbit, but by the time it exited the atmosphere, no fuel. I wasn't planning on refueling on EVERY landing.

So ... Technically success in that it can do the original job, but a failure as a boost glider since it needs constant refueling.

Might still be workable if you send it along with a refueling orbiter that you can rendezvous with every hop.

Do you get orbital speed? That's actually quite an accomplishment.

[Dientus]

13 hours ago, swjr-swis said:

Might still be workable if you send it along with a refueling orbiter that you can rendezvous with every hop.

Do you get orbital speed? That's actually quite an accomplishment.

When you said this, I realized you had a point. The amount of fuel feeding 2 RAPIERS leaving Eve? Quick math of what I remembered deltaV being on Kerbin didn't add up... So as soon as I could (RL happens), I set everything correct in the game, loaded, and ONLY cheated that craft to the surface of Eve, full tanks.

 

While it was impressive for what it is, it ran out of fuel before reaching orbit, so my last posted results were incorrect. My apologies guys. I will correct that.

 

For the record, thats why the orbiter is fat with a lot of delta-v, to refuel the Peryton. Just performed a skewed test. I've not given up, it DOES work on Kerbin, I need to test Laythe and Duna, but as built, not Eve.

[Dientus]

If anyone is still interested, I decided to upload the Peryton T1 to KerbalX

https://kerbalx.com/Deintus/Peryton-T1

Hopefully that is the right link The T1 (Type 1) has the main tank with Liquid Fuel only. Also, please note that this is only the Orbiter and the Peryton itself, it does not have a launch vehicle attached so will not get to LKO as is. That part is still WIP.

Also, it is modded. I believe the mods in this craft are:

DLC (both),

KSPIE 1.26,

NF Solar,

NF Electrical,

NF Aeronuatics,

Mk2 Xpansion 1.8,

Mk3 Xpansion 1.5,

AirplanePlus 26.5,

KAS1.7

 

I feel I am close to my goals, just taking time. To be a kid again

 

*Also, I have been making sure the Mk2 bi-coupler and Mk2 to 2.5 adapter that are located between the craft and the orbiter are empty on launch. If you don't mind @swjr-swis when you get a little time, could you verify the twin bicoupler/engine setup is only connected at one spot? I swear it seems both are connected, or I am just missing it when I go looking.

 

Edited April 17, 2021 by Dientus
Added bottom line

[swjr-swis]

4 hours ago, Dientus said:

If you don't mind @swjr-swis when you get a little time, could you verify the twin bicoupler/engine setup is only connected at one spot? I swear it seems both are connected, or I am just missing it when I go looking.

I can't load your craft, I don't have those mods installed. But it doesn't need any verification - it's just how KSP is programmed to work. Any parts or subassemblies added are attached either radially, or by one - and only one- attachment point.

Load your craft in the VAB. Grab either one of the RAPIER engines. The moment you detach the engine from the Peryton, you'll end up either holding an engine with the rest of the orbiter hanging from it, or just a single engine and nothing else (this is the engine that is NOT connected to the decoupler).

 

My advice is to replace that long Mk2 LF tank  on the Peryton by a cargo bay of the same size. That gives you two internal nodes, and enough space to later fit two Mk1 LF tanks, which is the same amount of fuel as the Mk2 tank. Put a docking port with the docking end on the top node. Attach a 3.5m fairing undere that port, and offset the port with fairing down to just under the RAPIERs. This is the new top of your orbiter now. Add 3.5m tanks as needed under the fairing, ending with the Rhino.

The fairing can be closed on the Mk2 body, but it will require removing the wings temporarily; you can replace them after and leave them partially sticking out. If you make sure one of the 'seams' of the fairing runs along the sides of the plane, the wings won't be harmed when the fairing deploys.

This will properly attach the Peryton dead center on top of the orbiter, and gives you a place to redock to refuel between hops.

 

[Dientus]

@swjr-swis  Thanx for your time.

 

Will definitely give that a shot.

Edited April 18, 2021 by Dientus
had to add the thanx lol