AeroTech Open Thread

[smstachwick]

Just a word of thanks @AeroTech for making the hilariously fun I200W. It's one of my faves, and burning one today half a year or so after the last one put a grin on my face that's still there. Flew it in a scratchbuild I based on Quest 50mm parts. That rocket was designed for the I200, but today was the first time I flew it on one. The near-instant teleport to 1,700 meters has me thinking I need to fly this motor minimum diameter in the not too distant future.

That thing is going to be a BEAST!

 

[kjhambrick]

Just a word of thanks @AeroTech for making the hilariously fun I200W. It's one of my faves, and burning one today half a year or so after the last one put a grin on my face that's still there. Flew it in a scratchbuild I based on Quest 50mm parts. That rocket was designed for the I200, but today was the first time I flew it on one. The near-instant teleport to 1,700 meters has me thinking I need to fly this motor minimum diameter in the not too distant future.

Woo Hoo Stephen !

Can't wait to see your pics !!

-- kjh

 

[bad_idea]

That thing is going to be a BEAST!

It will, but with my build rate of late, "soon" may turn into "2027."

Can't wait to see your pics !!

I need to get better at taking and posting those.

 

[kjhambrick]

I need to get better at taking and posting those.

No worries, Stephen -- you're MUCH better than I am with a camera

How is the weather up there in Seymour ?

-- kjh

 

[n3tjm]

Just a word of thanks @AeroTech for making the hilariously fun I200W. It's one of my faves, and burning one today half a year or so after the last one put a grin on my face that's still there. Flew it in a scratchbuild I based on Quest 50mm parts. That rocket was designed for the I200, but today was the first time I flew it on one. The near-instant teleport to 1,700 meters has me thinking I need to fly this motor minimum diameter in the not too distant future.

Don't forget about the DMS version of the I200, the I205! That motor is also a beast! Flew one in my LOC Vulcanite


The only thing I don't like about the I200 is it is more $ than its sister load, the H268. I once asked Gary why that was the case and he said because its a "I"... I don't quite understand that.. Same case, just different propellant, unless there is something I am completely missing here... I don't think there should be a price difference. The 38/360 doesn't charge any more between the H and I loads?

 

[boatgeek]

Don't forget about the DMS version of the I200, the I205! That motor is also a beast! Flew one in my LOC Vulcanite
View attachment 632502

The only thing I don't like about the I200 is it is more $ than its sister load, the H268. I once asked Gary why that was the case and he said because its a "I"... I don't quite understand that.. Same case, just different propellant, unless there is something I am completely missing here... I don't think there should be a price difference. The 38/360 doesn't charge any more between the H and I loads?

I'm guessing it's a case of pricing what the market will bear. Many people assess value by price/impulse class step rather than price/N-s. For them, an I will have more value than an H even if it's nearly the same impulse.

 

[rfjustin]

I was assembling an M1500G today and this is as far down as I could get the aft closure, and it does seem sealed as air pressure prevented me from putting the cap on easily. I vaguely remember seeing something saying this gap was allowed to be up to 1/8". Can anyone confirm that? The gap is just under 1/8".

View attachment 632433

What @tfish said, you are good to go sir.

 

[bad_idea]

No worries, Stephen -- you're MUCH better than I am with a camera

How is the weather up there in Seymour ?

Was gusty but reasonable yesterday and this morning until about ten o'clock, when the wind rose. UTSA flew their SRAD N motor around 11, last flight of the day, and it was drifting far and fast. Was sorry you couldn't make it.

Don't forget about the DMS version of the I200, the I205! That motor is also a beast! Flew one in my LOC Vulcanite

That's a great motor too, lighter and higher impulse than the I200. But the I200 is no-Hazmat, which is a big part of my love for it.

The only thing I don't like about the I200 is it is more $ than its sister load, the H268. I once asked Gary why that was the case and he said because its a "I"... I don't quite understand that.. Same case, just different propellant, unless there is something I am completely missing here... I don't think there should be a price difference. The 38/360 doesn't charge any more between the H and I loads?

It's a fair question. Baby I vs. max H, 13% more expensive, but only 4% more impulse.

For my part, the hammer the I200 gives off the pad (37% higher max thrust) and the lower average thrust (26% lower) are a better fit for both heavier rockets and for lighter rockets built for altitude. For instance, the rocket I flew yesterday sims 6% higher on the I200 than the H268, and a heavier rocket I fly on the I200 gets off the pad 11% faster. I'm willing to pay a little extra for that edge (though I'm not as ready to pony up for the I205 with Hazmat). Plus I find White Lightening a lot more inspiring than red propellants.

I think all that plus what Gary told you probably prices it appropriately vs. the H268. But if @AeroTech ever releases a 29/480 case and loads, I'll stretch all my rockets with 29mm mounts and forget about the 29/360 motors entirely. (Hint, hint. )

 

[terryg]

For my part, the hammer the I200 gives off the pad (37% higher max thrust if @AeroTech ever releases a 29/480 case and loads, I'll stretch all my rockets with 29mm mounts and forget about the 29/360 motors entirely. (Hint, hint. )

I would settle for hazmat free reload for the 38/480 case!

 

[bad_idea]

I would settle for hazmat free reload for the 38/480 case!

The no-Hazmat 38/1080 load ended up on the seasonal list. Shows what little I know about the market, since I would have figured that motor would be a best seller.

 

[kjhambrick]

Stephen --

I imagine you already know this but here goes ...

As of Feb 19, Harry did have three DMS I205W motors and his price for the I205W is just little lass than the RMS 29/360 I200W ...

-- kjh

Edit: grammar

 

[bad_idea]

As of Feb 19, Harry did have three DMS I205W motors and his price for the I205W is just little lass than the RMS 29/360 I200W ...

Yes, I had thought I would buy one of those, just to push my little 29/50mm rocket a tiny bit higher, but it's actually simming lower than the I200, for reasons I don't understand. Further digging required.

 

[terryg]

The problem with the seasonal J520W was that not that many folks have the 1080 case and it was priced the same as more powerful reloads. I have flown two of them and it is nice reload, but I can see why it is seasonal limited market. The 38/720 case is much more commonly available.

 

[bad_idea]

The problem with the seasonal J520W was that not that many folks have the 1080 case and it was priced the same as more powerful reloads. I have flown two of them and it is nice reload, but I can see why it is limited market. The 38/720 case is much more commonly available.

Good point. It would be interesting to see how a no-Hazmat J for the 38/720 would sell. But of course a lot more things are interesting to a sideline observer like me than are interesting to the business owner who has to take the risk on a new product.

 

[terryg]

Good point. It would be interesting to see how a no-Hazmat J for the 38/720 would sell. But of course a lot more things are interesting to a sideline observer like me than are interesting to the business owner who has to take the risk on a new product.

I am not sure a non-hazmat J is possible in the 720 case without blowing up the case. But a more powerful "I" would be great for those birds that need a little bit more punch.

 

[dhbarr]

I am not sure a non-hazmat J is possible in the 720 case without blowing up the case. But a more powerful "I" would be great for those birds that need a little bit more punch.

How many grams in each i600r or j500g slug?

 

[n3tjm]

I too really wish there was an USPS shippable load for the 480 case.

 

[SolarYellow]

Yes, I had thought I would buy one of those, just to push my little 29/50mm rocket a tiny bit higher, but it's actually simming lower than the I200, for reasons I don't understand. Further digging required.

I'd be interested to see the graphs of both sims overlaid.

 

[SolarYellow]

But if @AeroTech ever releases a 29/480 case and loads, I'll stretch all my rockets with 29mm mounts and forget about the 29/360 motors entirely. (Hint, hint. )

I suspect the length or aspect ratio might become a bit of an issue, leading to diminishing returns making a 29/480 look not as attractive as you're thinking.

I was looking at the assembly drawings of the 180, 240 and 360 W loads recently, and it appears to really be "one sausage, three lengths." Very elegant. Perhaps that just doesn't work as well at the next step.

 

[John From Oregon]

I have a 54/1706 case with the extended plugged forward closure (54FCEPT). For reloads that don't require the extended closure, is there much risk in just swapping out the delay grain insulator and spacer for longer ones from RCS? It seems that a reasonable alternative to buying a standard closure (acknowledging this would de facto be a research motor if I do this).

 

[WillMarchant]

Any news on the iLaunch? And I’ve been thinking about the fact that it ties up your iPhone during the launch. I often want to photo or video the takeoff so I’d have to have somebody else do either launch control or photography on their phone.

I guess I’m thinking it would be nice if a dedicated wireless control box was available as an option. Or publish the interface specs so we could program up a Raspberry Pi, or similar, to have a “launch button” and safety interface.

 

[jd2cylman]

I was assembling an M1500G today and this is as far down as I could get the aft closure, and it does seem sealed as air pressure prevented me from putting the cap on easily. I vaguely remember seeing something saying this gap was allowed to be up to 1/8". Can anyone confirm that? The gap is just under 1/8".

View attachment 632433

The new information about Aerotech making the lines longer means that if the gap looks to big, the consensus is to loosen the forward closure and split the difference. Making sure no threads are showing at either end.

 

[mh9162013]

I guess I’m thinking it would be nice if a dedicated wireless control box was available as an option.

Might be easier/cheaper to get an old, used smartphone to be your dedicated launch controller.

 

[kjhambrick]

The new information about Aerotech making the lines longer means that if the gap looks to big, the consensus is to loosen the forward closure and split the difference. Making sure no threads are showing at either end.

Wait !

What concensus is that ?

-- kjh

 

[Banzai88]

Wait !

What concensus is that ?

-- kjh

Yeah, I'm going to +1 that. I just searched all through the thread......many times they say directly to make sure the top closure is firmly seated and leave the gap at the nozzle end closure ONLY.

Have yet to find a post where they say to split the gap.....maybe I missed it?

 

[Theory]

Cool, thanks. My main concern was whether it would be able to fly safely on the new K750ST. Seems like it definitely could with that weight.

Yeah, I'm going to +1 that. I just searched all through the thread......many times they say directly to make sure the top closure is firmly seated and leave the gap at the nozzle end closure ONLY.

Have yet to find a post where they say to split the gap.....maybe I missed it?

this was my understanding as well. never heard AT recommending to have a gap at the FWD end

 

[jd2cylman]

this was my understanding as well. never heard AT recommending to have a gap at the FWD end

Me neither until I was told that now that the liners are longer. I guess we’ll need @AeroTech to chime in… but that’s what my motor dealer says to do now.

 

[rfjustin]

Me neither until I was told that now that the liners are longer. I guess we’ll need @AeroTech to chime in… but that’s what my motor dealer says to do now.

I've heard that relating to 98mm only, no other sizes.

 

[BEC]

Any news on the iLaunch? And I’ve been thinking about the fact that it ties up your iPhone during the launch. I often want to photo or video the takeoff so I’d have to have somebody else do either launch control or photography on their phone.

I guess I’m thinking it would be nice if a dedicated wireless control box was available as an option. Or publish the interface specs so we could program up a Raspberry Pi, or similar, to have a “launch button” and safety interface.

I’ve been wondering about that myself. That other bluetooth launch controller from some years ago (BlueNose MMC) had this problem…couldn’t take pictures/video while using it, and it launched an automated countdown — no need to hold virtual buttons down to get it to launch though there was an “abort” you could tap once the countdown was underway. But rather than a Raspberry Pi I was thinking about an older and no-longer-in-use iPhone, though I am not sure how I’d get the iLaunch app onto one I have laying around.

I sometimes take this iPad to a launch, so maybe I’ll use it for the iLaunch so my phone is free to take video/photos and manage my FlightSketch altimeters.

 

[BEC]

On a vaguely related note, @AeroTech what are the chances that the B14Ts will be available in sufficient time to be NAR Contest Approved for NARAM this year? I dropped Karl a note about that, but I’m sure I’m not the only one wondering….