[SS-VehDev] Re: [Fwd: Re: [SS-Main] new Propellant Team member]

Fri Oct 7 13:31:19 PDT 2005

Ah, that low. You are right.

When were we talking about introducing spin for stabilization? If the
spin up has already happend we have less need for fin.

Matt C (California)

On 10/7/05, Hans Olaf Toft <hot at vip.cybercity.dk> wrote:
>
> Good evening Matt ;-)
> I don't know where You are located, but it is 7.30 in the evening here
> in Denmark.
>
> I made this configuration for the nose drag simulations. There had to be
> some fins - and I made a quick guess. Size and shape is up for
> negotiations, but it will be something in that range. longer root cord
> and less span is a good idea. We should go for making the fins as thin
> as possible.
>
> I have burnout at 13.6km, and fins are needed very much at the peak
> velocity.
>
> /Hans
> Lakestake Rocketry wrote:
>
> >Good morning Hans,
> >
> >What altitude will you be at at burnout? I would assume we will be high
> >enough that the fins won't make a darned bit of difference...
> >
> >Nice looking rocket. Just about what I have seen other team members
> >come up with.
> >
> >When I was playing around with designs I had pushed the fins forward
> >one caliber to reduce drag.
> >
> >I used a longer root chord for better fin stability at or over mach.
> >I don't remember if we were going to stay under mach during
> >the first phase burn.
> >
> >I used less span (less effective) with more area (higher drag) for
> >stability of the fin at high speed. I have found in practice that
> >having a lower profile fin allows me to get away with a thinner
> >fin (less overall drag) with better rigidity.
> >
> >Once we have more details from Richard about the motor
> >including CG, weight and thrust curves we can start fine tuning
> >the fins a lot more. I am eagerly awaiting the aerospace
> >professionals here to chip in with more things to think of when
> >considering fin design for larger projects.
> >
> >Matt C
> >
> >On 10/7/05, Hans Olaf Toft <hot at vip.cybercity.dk> wrote:
> >
> >
> >>The current guess on the CG is 5172mm (from tip of nose) loaded, and
> >>4632mm empty. I will have to study the drawing of the 1/4 scale motor to
> >>possibly refine this guess, but it is only going to change slightly.
> >>
> >>The shown configuration would have a 3.6 caliber staic margin at burnout
> >>with 4 fins or 1.4 calibers with 3 fins - just to get an idea of the
> >>required fin size.
> >>
> >>/Hans
> >>
> >>Lakestake Rocketry wrote:
> >>
> >>
> >>
> >>>Hi Richard,
> >>>
> >>>We have done some analysis on nose design, but I don't know who was
> >>>
> >>>
> >>'first
> >>
> >>
> >>>on the list'. Bill had put together an analysis spreadsheet we were
> going
> >>>
> >>>
> >>to
> >>
> >>
> >>>use, but I don't know if anyone has put the two together yet.
> >>>
> >>>I have been playing a bit with fin designs, but until I know more about
> >>>
> >>>
> >>the
> >>
> >>
> >>>rocket there is little to go on. Again I don't know what Bill has been
> >>>working
> >>>on or if anyone else in the group has been working on this. Anyone?
> >>>
> >>>Before fin design can be finalized we need to know what the engine
> casing
> >>>requirements will be, what the aft closure is going to look like, and
> >>>
> >>>
> >>what
> >>
> >>
> >>>the
> >>>engine thrust curve looks like. I usually design the fins last once the
> >>>
> >>>
> >>rest
> >>
> >>
> >>>of
> >>>the rocket has been finalized.
> >>>
> >>>Again there is a lot of experience in this group, can someone with more
> >>>design
> >>>experience step up here?
> >>>
> >>>Matt C
> >>>
> >>>On 10/6/05, Rich Nakka <richnakka at rogers.com> wrote:
> >>>
> >>>
> >>>
> >>>
> >>>>Vehicle Team gents,
> >>>>I know that BC is away for some time, perhaps someone could let me
> know
> >>>>what size/type nosecone is currently #1 on the list. Also fins
> >>>>
> >>>>
> >>specifics, if
> >>
> >>
> >>>>such currently exists...
> >>>>TIA.
> >>>>Richard
> >>>>
> >>>>-------- Original Message -------- Subject: Re: [SS-Main] new
> Propellant
> >>>>Team member Date: Thu, 6 Oct 2005 13:46:30 -0300 From: Miraglia
> >>>><miragli at terra.com.br> <miragli at terra.com.br> To: Rich Nakka
> >>>><richnakka at rogers.com> <richnakka at rogers.com> References:
> >>>><20051004020508.42809.qmail at web80804.mail.yahoo.com><
> >>>>
> >>>>
> >>20051004020508.42809.qmail at web80804.mail.yahoo.com>
> >>
> >>
> >>>><4341E5E9.5010600 at rogers.com> <4341E5E9.5010600 at rogers.com><
> >>>>002501c5c8f9$5e928640$d498abc8 at piii750> <43445604.3090704 at rogers.com><
> >>>>
> >>>>
> >>43445604.3090704 at rogers.com>
> >>
> >>
> >>>>Dear Richard
> >>>>
> >>>>I received the CD, thank you very much.
> >>>>
> >>>>I agree in to simulate the two possibilities with launch lug and
> >>>>
> >>>>
> >>lugless.
> >>
> >>
> >>>>I am awaiting the dimensions of the rocket to begin the simulations.
> >>>>
> >>>>Thank you
> >>>>
> >>>>Miraglia
> >>>>
> >>>>----- Original Message -----
> >>>>*From:* Rich Nakka <richnakka at rogers.com>
> >>>>*To:* Miraglia <miragli at terra.com.br>
> >>>>*Cc:* Sugar Shot <ss-main at sugarshot.org>
> >>>>*Sent:* Wednesday, October 05, 2005 7:39 PM
> >>>>*Subject:* Re: [SS-Main] new Propellant Team member
> >>>>
> >>>>Miraglia wrote:
> >>>>
> >>>>Dear Rich
> >>>>
> >>>>I am in favor of the solution " lugless "
> >>>>
> >>>>The problem will be with the project of the launch ramp.
> >>>>
> >>>>cheers
> >>>>
> >>>>Miraglia
> >>>>
> >>>>Lugless should certainly be considered, but should be chosen only if
> >>>>justified. The complexities of the launch tower design & fabrication
> >>>>
> >>>>
> >>would
> >>
> >>
> >>>>presumably be that much greater, and I would expect failure risk would
> >>>>increase too (isn't this so, Matthew?).
> >>>>A drag study should be conducted to compare the vehicle with/without
> >>>>
> >>>>
> >>lugs.
> >>
> >>
> >>>>Richard
> >>>>
> >>>>
> >>>>
> >>>>----- Original Message -----
> >>>>From: Rich Nakka
> >>>>To: miragli at terra.com.br
> >>>>Cc: Sugar Shot
> >>>>
> >>>>Sent: Monday, October 03, 2005 11:16 PM
> >>>>Subject: Re: [SS-Main] new Propellant Team member
> >>>>
> >>>>
> >>>>By the way, Jose, I forgot to mention that you should sign up to the
> >>>>
> >>>>
> >>Sugar Shot to Space e-mail discussion forum:
> >>
> >>
> >>>>http://www.exrocketry.net/mailman/listinfo/ss-main
> >>>>
> >>>>to keep up with the latest developments.
> >>>>
> >>>>
> >>>>cheers
> >>>>Richard
> >>>>---
> >>>>
> >>>>
> >>>>william colburn wrote:
> >>>>
> >>>>Jose,
> >>>>
> >>>>I second Rich's welcome.
> >>>>
> >>>>The vehicle as it stand now will have either a
> >>>>straight 5.5 aspect ratio conical NC or a 3/4 Power NC
> >>>>
> >>>>of the same aspect ratio.
> >>>>
> >>>>The fins are not designed. We want a minimum area both
> >>>>frontal and surface of course. They must be designed
> >>>>to be rigid against the tendency to flutter at any
> >>>>Mach number and altitude we experience.
> >>>>
> >>>>
> >>>>Rich can provide a detailed Velocity vs Altitude and
> >>>>also impact pressure estimate.
> >>>>
> >>>>The vehicle is unique in that in incorporates a coast
> >>>>period before lighting up the second burn. This
> >>>>reduces the drag integral allowing more effective use
> >>>>
> >>>>of the onboard propellant.
> >>>>
> >>>>We can provide cartoons at this point of general
> >>>>layout we anticipate, an intitial estimate of the fin
> >>>>shape and size, and the two NC shapes.
> >>>>
> >>>>Will that be enough for you to initiate a CFD analysis
> >>>>
> >>>>of the worst case condition?
> >>>>
> >>>>BC
> >>>>
> >>>>--- Rich Nakka <richnakka at rogers.com> <richnakka at rogers.com> wrote:
> >>>>
> >>>>
> >>>>José,
> >>>>Thanks again for your offer, and welcome to the
> >>>>Project's " Propellant
> >>>>Development Team " .
> >>>>
> >>>>With regard to CFD, I think it'd be a great idea to
> >>>>model our vehicle
> >>>>using CFD to get a better indication of drag, which
> >>>>
> >>>>could allow us to
> >>>>refine our simulations. Bill Colburn
> >>>>(space1space at sbcglobal.net) is the
> >>>>
> >>>>Vehicle Development Team Lead and he can fill you in
> >>>>on details. I
> >>>>should point out that the vehicle is not defined
> >>>>yet, I believe the
> >>>>nosecone and fins are being studied...BC could
> >>>>provide more up-to-date
> >>>>
> >>>>details.
> >>>>
> >>>>I think a CFD model of the vehicle on our website
> >>>>would look awesome ;-)
> >>>>
> >>>>Something that might be studied is the effect of
> >>>>launch lugs on vehicle
> >>>>drag? This would be of aid to the Launch Support
> >>>>
> >>>>Team, who are
> >>>>particularly keen on knowing whether or not we
> >>>>should go "lugless".
> >>>>
> >>>>Richard
> >>>>
> >>>>-------------------------------
> >>>>Dear Richard
> >>>>
> >>>>Thank you for its fast answer.
> >>>>
> >>>>
> >>>>I would like to participate of the project " Sugar
> >>>>Shot to Space ".
> >>>>
> >>>>I am chemical engineer, master degree in rocket
> >>>>propulsion and
> >>>>university teacher.
> >>>>
> >>>>Now I am coordinating a team for the development of
> >>>>
> >>>>a liquid propellant
> >>>>rocket engine (H2O2/Ethanol) for the project
> >>>>SARA. http://www.iae.cta.br/sara.htm
> >>>>
> >>>>
> >>>>I is also specialist in CFD.
> >>>>
> >>>>Already 20 years ago I develop amateur rocket
> >>>>propellants. I use NaNO3 +
> >>>>Sugar.
> >>>>
> >>>>I obtained excellent results.
> >>>>
> >>>>Rocket propulsion is my life.
> >>>>
> >>>>
> >>>>If possible I would like to participate in "
> >>>>Propellant Development Team "
> >>>>
> >>>>How can I help?
> >>>>
> >>>>Thank you
> >>>>
> >>>>José Miraglia
> >>>>_______________________________________________
> >>>>SS-Main mailing list
> >>>>
> >>>>SS-Main at sugarshot.org
> >>>>
> >>>>http://www.exrocketry.net/mailman/listinfo/ss-main
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
>
> >>>>------------------------------------------------------------------------------
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> >>
> >
> >
> >
>
>
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