AT Midpower poll

[Bowhunter]

G-80 redline would be cool

 

[Ryan S.]

I think it would be pretty cool, I probably wouldnt buy them, but they would be cool

 

[rstaff3]

Supposedly they are going to make a Redline load for the 29/120 case. The average impulse probably will be a bit above 80.

 

[Donaldsrockets]

Originally posted by rstaff3
Supposedly they are going to make a Redline load for the 29/120 case. The average impulse probably will be a bit above 80.

Yeah, it will probably be a G85-G90R, somewhere around there. I'd buy them. Those would be great motors for my PML Explorer and Small Endeavour.

I also heard that they plan on making a Redline load for the 38/120 casing as well. That would probably be a G70R or something.

 

[Ryan S.]

nice high thrust G motor, for those rockets that can ususally only take a G80

 

[rstaff3]

A G90 would be good for several of my rockets, Small Endeavour included. I really would like a G120 for the 38/120 case. I have several rockets that need that much avg impulse.

 

[hokkyokusei]

"Don't tease me"

I'd like to see _any_ new shipment Aerotech motors in the UK, especially reloads. It would be nice to get some use from my expensive set of wind chimes.

 

[als57]

It seems like Joe Burger was broadly hinting the Redlines (and other types) would be available for the new cases. Makes sense if they are the same grains as the normal HP loads use.



Al
BRS VP

 

[marvSRG]

This sounds really interesting, but what's odd to me is that I've e-mailed Gary Rosenfield and he informed me that it's not likely for any Redlines to come out for the hobby case because it does not show up very well under 160NS and in the c-slot grain format used in that case. Maybe we're about to see the first bates grain 40-120 load, or maybe a new formulation of Redline. They have two or three versions of White Lightning anyways...better get started w/Redline. I'll keep my eyes open, though...a hobby case Redline sounds pretty awesome.

Personally I'm really glad that AT has kept up it's midpower line because other than Ellis (which I do like as well) and those terribly expensive 1-grain Pro38's, it's all midpower has, and it's the only thing with variety in propellant and motor size...especially with the new 38mm G. Just wish the prices went down....

 

[als57]

The new 29/120 case is not the hobby line case. Its essentally a shorter version of the 29/180 case ( 2 grains vs 3 ). So issues with c-sloted grains are moot. As for the other issues ; being worked on. Lets hope they are sucessful.



Al
BRS VP

 

[Austin]

they would be nice to see...I would like to see more come out with the single grain 38mm.

Carl

 

[marvSRG]

Originally posted by als57
The new 29/120 case is not the hobby line case. Its essentally a shorter version of the 29/180 case ( 2 grains vs 3 ). So issues with c-sloted grains are moot. As for the other issues ; being worked on. Lets hope they are sucessful.

Oops...should've read more carefully. I thought rstaff3 said the new Redlines would be for the hobby 40-120 case. The "120" made me think that...gotta get used to that being it's own case now. Yeah, that idea should work extremely well for that case, then.

 

[als57]

And the G61 load for the 38mm is basically a single grain load ( vs 2 for the H123 ) so hopefully we'll see the other propellant types here as well.

I was fortunate enough to buy cases and loads at LDRS. Hope to fly some in a couple weeks at our next launch. The G61's I saw fly seem a bit less enerjetic than the CTI 1 grain loads. But they cost a heck of a lot less.


Al
BRS VP

 

[Thrasher]

I can't imagine AT being able to get a G "redline" in a 40-120 and keep it under 62.5 grams. They don't have to keep it under 62.5, but it does solve some problems. The G64 is at the limit and the G33 is over the limit. It's good to keep the hobby line below 62.5 grams. Of course, the only redline I've used is a J420R, so what do I know.

 

[marvSRG]

Originally posted by Thrasher
I can't imagine AT being able to get a G "redline" in a 40-120 and keep it under 62.5 grams. They don't have to keep it under 62.5, but it does solve some problems. The G64 is at the limit and the G33 is over the limit. It's good to keep the hobby line below 62.5 grams. Of course, the only redline I've used is a J420R, so what do I know.

Actually, I don't see why there would be a weight problem w/a 29mm 40-120 Redline load because in weight comparisons (due to Tripoli motor data comparing the J420R and the J350W- both of which use the same case), Redline appears to be slightly lighter than WL, and if that's due to a larger core size (which I doubt) the weight would probably come out about the same. The exact readings were J350W: 361.1g and the J420R: 345g. So a Redline for the 40-120 would work out weight wise...the only reason the G33J is above 62.5g is because that's a heavy propellant due to the smoke making ingredients in the propellant (zinc, I believe...like most black propellant).

But due to what I've heard, visually, the brilliant flame doesn't show up as well in the 40-120 setup, so for that reason they probably won't make a load for that case. But at any rate, the loads being spoken of here are loads for the new 29/120 case, which is new and is compatible with the HPR hardware (a step above the 29/100 case which uses such reloads as the G104T). Like you, I also thought that they were talking about the 40-120 case, but it's this new one, which threw me off. And as for this case, the G79W works great, and weight wise, I don't see why a Redline wouldn't work...just a little less power. And because this is a bates grain setup, I don't think there will be any issues with the visual aspect of the motor as the 40-120 setup would be a c-slot, which from what I understand is what hinders the visual aspect.

At any rate, a Redline 29/120 load would be awesome, and I would look into it if it came out.

 

[rstaff3]

If there were a tad more propellant weight this could be fixed by adjusting the core, like what has been done with the I600 vs the J420.

 

[marvSRG]

Originally posted by rstaff3
If there were a tad more propellant weight this could be fixed by adjusting the core, like what has been done with the I600 vs the J420.

Exactly...didn't they do that w/all the Pro38 classic loads for weight issues? If so, why not SS's? I seem to remember that Pro38 SS's were the only 38mm reloads that needed a LEUP back in the days of easy access. Would doing that result in too high avg. thrust or undesirable performance for those motors?

 

[n3tjm]

I believe C-Slot motors opperate at a lower pressure rate then Bates Grains. Pressure can make a big difference on how a propellant performs. For example, some black propellant I burn burns white outside the motor case when I burn small samples.. yet thick black in a motor. The H128 (probabily the G79 too) - I200 operate at the same Internal Presure... which is the reason why they share the same delay grains.

 

[Ryan S.]

Originally posted by n3tjm
I believe C-Slot motors opperate at a lower pressure rate then Bates Grains. Pressure can make a big difference on how a propellant performs. For example, some black propellant I burn burns white outside the motor case when I burn small samples.. yet thick black in a motor. The H128 (probabily the G79 too) - I200 operate at the same Internal Presure... which is the reason why they share the same delay grains.

this is not always true, pressure is related to the KN of a motor (so nozzle throat ccould be reduced in a C slot and therefore you could have the exact same pressure in a bates grain motor) another thing (amount many things) is burn rate. So if you have a fast burning propellant your pressure, in a C-slot motor, could be higher. Pressure is only partially determined by grain configuration, there are many other variables that factor into pressure of a motor, so you cannot say that C-Slots operate at a lower pressure. Remember, all AP motors need to operate at a certian pressure in order to vaporize the ingredients to induce burning so the pressure difference, assuming there is one, is not going to be much higher.

the reason your black isnt that smokey is because your temperatures are not very high. I have however burned smokey grains outside and the smoke was black so....

 

[n3tjm]

Let me add another element to the equation... the hobbyline of RMS motors operate at lower pressure than the High Power line. Notice the number of threads on the hobby line compaired to the High Power line? That is why there is not Blue thunder loads greater than F. I beleive I heard that they tried making blue thunder G's for that 40-120 case, but kept blowing them up. I am not sure how true that is, but it makes since to me.

 

[Ryan S.]

you need to remember that total pressure is dependent on Total area. You dont need as many threads on a smaller case, because the total pressure simply is not as much. When you have a 1" square circle and a 2" square circle the pressure on the 2" will be more and you need thicker closures, even if the pressure/inch^2 is the same in both cases.

I would be willing to bet they couldnt do bigger blues because they could not insulate the case agianst the extreme heat that blue propellant puts on cases, in a C-slot load this would be a major problem

 

[marvSRG]

To slightly divert the conversation but related- why haven't we seen any bates loads for the hobby line? Can the case not take the higher average thrust that results? Or did AT decide against it because the setup would result in much higher thrust motors and they wanted more "mellow" motors for this line?

Let me add another element to the equation... the hobbyline of RMS motors operate at lower pressure than the High Power line. Notice the number of threads on the hobby line compaired to the High Power line? That is why there is not Blue thunder loads greater than F. I beleive I heard that they tried making blue thunder G's for that 40-120 case, but kept blowing them up. I am not sure how true that is, but it makes since to me.

The question is why do the operate at a lower pressure? I'm assuming by design and not solely from the c-slot format. If by design, couldn't successful BT G motor tests result from altering the design of the load (including grain geometry), or are you only referring to the c-slot grain pattern?

 

[als57]

Originally posted by Thrasher
I can't imagine AT being able to get a G "redline" in a 40-120 and keep it under 62.5 grams. They don't have to keep it under 62.5, but it does solve some problems. The G64 is at the limit and the G33 is over the limit. It's good to keep the hobby line below 62.5 grams. Of course, the only redline I've used is a J420R, so what do I know.

The newly released 29/120 and 38/120 cases are shorter versions of the HPR cases. Redlines and other formulations have been hinted at by Gary and Joe for these cases. Makes sense : same case strenght , same grain structure. Unless there is an issue with propellent mass.

The propellant load in both cases is <62.5 gr. They might have a issue with the weight of a black jack reload ; but the others should be OK from a weight point of view.

As for the hobbyline 29/40-120 ; probably not going to happen for some of the reasons mentioned here. Also I have heard there are issues with the c-slot grains and liner burn thru with redlines and blue thunder.

At least we're seeing some new stuff. And that's a good thing.


Al
BRS VP

 

[artu]

OK,

I'm no expert,

But I think the reason you don't see HOT motors for the 29/40-120 is not only the need that its a consumer motor,

but also that as a consumer, it must have a Average thurst lower or equal to 80ns. anyting else is HPR, even if a "G".

if the White Light propel produces 64ns average, BT, RL might produce a bit more then 80 maybe in the molds they are using.

OK, if you re-engineered the whole thing, you could get a Red Line to work under 80ns in that case. However, that would take quite a bit of re-engineering, or money invested.

I think the new 29 and 38 "G" cases will be the ones you see the KEWL stuff in.

SO, go buy the new 120 cases and enjoy !

ArtU

 

[marvSRG]

Great points artu. Most people look over that 80ns avg. thrust rule.

 

[n3tjm]

Originally posted by marvSRG
The question is why do the operate at a lower pressure? I'm assuming by design and not solely from the c-slot format. If by design, couldn't successful BT G motor tests result from altering the design of the load (including grain geometry), or are you only referring to the c-slot grain pattern?

Grain Geometry. With most designs, C-Slot motors have less initial surface area then Bates grain. You can increase the presure by putting a smaller nozzle in it, but you can only do that so far... before you blow the nozzle or case....